It's a mixed bag for sure.
It is good and right to believe in the scriptures of the current Bible, as it is the providence of God and not of men. Many will argue from all sorts of different angles. Nonetheless, it is God who decides what goes out to each generation.
Personally, in a word, I would say, Yes, I believe in the Trinity. However, it is also clear that the scriptures are written to children of slow learning...that is, His thoughts (and the actual truth) is higher by far, and we are His children.
What I gather, is that God was and is One from the beginning, but then in the fullness of time He foretold, sent, and introduced His Son, and likewise, in the fullness of time, Jesus (according to the scriptures) fulfilled what was written and foretold of God pouring out His spirit upon all flesh, at which time the Son then sent, and introduced the Holy Spirit...which makes up the Trinity. That is the core of what God has given as the make up of God, each by Name. And yet it is also true that God has even many more Names. The point being that Three is not against the scriptures, and yet as words to children, I should think it wise to wait to hear the end of it with maturity...in the fullness of time.