I don't understand the trinity and never knew about it being taught until I was grown. I remember mentioning to my mom once and she was confused as to where that came from too. I do believe in the 3 being as of one. Same thoughts same everything. To me even if we find someone whose views are almost identical to our own we will never find one with the exact same thoughts same  everything . 

I can remember thinking ,like you ,as to where does people get the trinity beliefs. But now I believe they are one.  I don't believe everything Im told about scripture either. I just know I started to believe it. I remember they told me about something in Genesis and different things in the bible both old testament and new  .

The Trinity isn't mentioned in the Bible, and as Amanda said, neither is the Bible.  Neither are cars, since none of them were words that were thought of then.  And I've heard that hell was never in the Bible either, but that they used hell to encompass what the context was saying regarding Sheol, Hades and Gehenna.  And by the way, heaven also wasn't in the Bible.  Jesus called it paradise, and that actually may not even be the proper term.  Translators translated from old dead languages from people who lived in another time with different customs.  Using historical events to understand their times, context, etc., they developed more modern words that they used to describe the meaning behind the ancient Greek and Hebrew texts.  Therefore, since the Holy Trinity isn't in the Bible (or scripture as it is referred to), we have to use the context to grasp the meaning.  Trinity is a word designed to refer to many verses throughout the Bible.

Here are just a few that show the concept of a Trinity (or Triune God).  Triune is a Latin word whose first known use is from the early 1600's.  So 1600 years after Christ, they develop a word to describe Him, and it means: consisting of three parts, members, or aspects.

John 1:1: In the beginning was the Word, and the Word was with God, and the Word was God.

So if the Word was God:

John 1:14: And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth.

So now we know Jesus was the only begotten (Son) of the Father (God), and He was the Word and the Word was God.  Therefore, we now know Jesus was God...in the flesh.

And there are several verses about the Holy Spirit in us, here are two:  1 Corinthians 3:16: Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you?  and 2 Timothy 1:4:  That good thing which was committed unto thee keep by the Holy Ghost which dwelleth in us.

So now we know the Holy Ghost/Spirit is in us and He is the Spirit of God.

Also Jesus tells us in John 14: 15-17: If ye love me, keep my commandments.  And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;  Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.

But He says He will pray the Father (talking like He's not the Father) to send us another Comforter (like the other Comforter is also a separate entity. 

Yet then we have Ephesians 4:6: One God and Father of all, who is above all, and through all, and in you all.

So is God in us or the Holy Spirit?  And if both God and the Holy Spirit are in us, does that mean they are one and the same and yet separate. 

The key is that we cannot understand all there is to God while in the flesh.  1 Corinthians 13:9-10: For we know in part, and we prophesy in part. But when that which is perfect is come, then that which is in part shall be done away. and 1 Corinthians 13:12: For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.

So we try to explain God with human terms that endeavor to encompass that He is One being (as stated) but three separate (as shown in scripture).  We try to use references such as eggs consisting of yoke, white and shell, or people consisting of mind, body and spirit.  But in our humanness, we can in no way accurately describe it, so we use words such as trinity and triune to try and put them in a form we can grasp. 

As for Jesus not knowing the day He was returning...He was made flesh, He willingly came down in the flesh.  He gave up His place in heaven/paradise and His omnipresence, omnipotence and omniscience.  Which are also not original terms. 

I gathered these excerpts from http://www.cogwriter.com/god-omnipotent-omniscient-omnipresent.htm: 

The Greek word translated as “Omnipotent” here is pantokrator, meaning “All-ruling”or (as it is more frequently translated) “Almighty.” When we say God is “Almighty,” we are stating our belief in His authority and rulership over all creation, and the Bible is firm in declaring this fact. Even though Satan is now the “god of this age” (2 Corinthians 4:4), it belongs to him only because Almighty God has granted it to Him.  There is even a verse that, in the King James Version and New King James Version, uses this very word: “Alleluia! For the Lord God Omnipotent reigns!” (Revelation 19:6).

Being omnipresent means being present everywhere at the same time. Can this term be applied to God?  King David posed this question directly, asking: “Where can I go from Your Spirit? Or where can I flee from Your presence? If I ascend into heaven, You are there; if I make my bed in hell [the grave], behold, You are there. If I take the wings of the morning, and dwell in the uttermost parts of the sea, even there Your hand shall lead me, and Your right hand shall hold me” (Psalm 139:7–10).

The Random House Unabridged Dictionary (2006) offers this definition of omniscient: “having complete or unlimited knowledge, awareness, or understanding; perceiving all things.”  The Bible tells us that God does perceive all things, which means that no fact can be hidden from His knowledge. As King David recognized: “Indeed, the darkness shall not hide from You, but the night shines as the day; the darkness and the light are both alike to You” (Psalm 139:12). God sees all things, and nothing can be hidden from His knowledge—not even the secret intentions of the heart (Psalm 44:21). In fact, He understands our own intentions better than we do (cf. Jeremiah 17:9-10; Hebrews 4:12)! As Paul explains, “there is no creature hidden from His sight, but all things are naked and open to the eyes of Him to whom we must give account” (Hebrews 4:13).

It also states:  Human beings perceive through the senses, but there are limits to what the senses let us perceive and understand.

Which may explain why Jesus didn't know the day of His return.  But since we can now only know in part, we can only truly guess at it unless it is revealed to us.  Which is usually done through reading and studying scripture and taking it all in context.  And we still have our limitations on how to describe it.

I'm not asking you to bow out of the conversation Amanda....just that this discussion kind of took a turn to Church Membership & the early Church history. 

I am glad that you clarified points about Church Membership.  Anybody can be a member of a Church really...some don't ever attend...that's more or less about numbers IMO.  

Assembling together with other believers is what is really important, those who believe God's Word.  That's greatly important.  It's not every Christian that has an opportunity to belong to a Church, if you look into missions, some of them have to meet in secret.

As to the Early Church History, I think if you'd like, it would be a really great discussion to open.  

I hope you understand where I'm coming from.  

The Trinity in my opinion is a difficult thing to discuss, yet it's fundamental in it's value as to the Gospel.  Sometimes getting asked a question you don't know how to explain leaves you searching for answers.