Where ever did you get the idea that the first creed didn't come into existence for "centuries"? Not only does the Bible contain dozens (if not hundreds) of creeds, confessions, and catechisms, but Irenaeus' Rule of Faith, which many scholars consider to be the first extra-Biblical creed.
What you seem to be overlooking is that, typically, the purpose of creeds was to address an problem with doctrine in the church and to defend sound doctrine. The very fact that these problems arose without a creed and that a creed was needed to defend against them shows the necessity for creeds.
I don't know if you're aware of this, but the Old Testament, "the writings of Paul, Peter, Matthew, Mark, Luke, John, etc" all contain creedal statments and confessions. What are the writings of Paul and Peter if not a catechism for the church?
I disagree. Does your church have a statement of faith? How does your church differentiate its beliefs from those of the Mormon stake across town?
Amen. All this is very true, and to the heart of the matter. There were creeds in existence before the writing of the NT, and Paul quotes some of them. The first in writing that I know of is the Didache, which was 1st century.
The early church was not in a state of bliss. It had troubles and arguments and disagreements just like today.....1st Corinthians was written to solve many issues that had already cropped up. Several of the other NT books were written to specifically combat false teachings that had already popped up.
Creeds merely clarify what we believe, and don't take the place of scripture. They were all in response to correcting false teachings that were dividing the church.
Those who today say that creeds cause division and try to only use the scirptures without a summary of their beliefs, do so in the name of unity. Ironically, those are the churches that have had more splits and divisions than the ones who can agree on a creed or doctrinal statement. For example, the Churches of Christ proudly and loudly will tell you that they follow no creed, only the bible. But their history is an exercise in church splits, divisions, and arguments. Without some summary of their beliefs that they all agree on, they've split over everything from communion cups to pitch-pipes, what to call the preacher, what to name the church, etc.
So the divisions in church history are real, and are sometimes good, often sinful. But the divisions are caused by the sinful humans, not the creeds or doctrinal statements. As human as the creeds may be, they have prevented far more arguments than they have caused.
We are in danger of losing the classic doctrines of our faith because we don't study them.
But as has been said here, mental assertion of a statement does not a Christian make.