I was raised Catholic (like Augustine was) and always knew about God.
When I was about 27 or so I was having a problem and prayed about it. I turned to Him and He spoke to my heart and told me something about the problem that really helped me a lot, then and for the rest of my life.
God reveals Himself to us.
But we have to say YES to Him.
In every other religion man is trying to reach up to God.
In our "religion" God is always reaching down to us. All we have to do is say yes to Him and trust in Him.
My part was believing and trusting in Him.