I don’t want to be rude, but you should not compare these two views. They are different in base, because Agnosticism is a view on world understanding[you can be faithful/unfaithful yet agnostic] and Atheism is view just on faith/religion matter[it’s kinda funny, but we can say that atheist can’t be agnostic].
I was raised in christian faith, but now I’m atheist. It began in normal teenage rebellion against everything: parents, system, church/faith almost like anarchy because it often suits young people. When I got adult, more educated and gain knowledge how things work in life I found atheism most rational view on faith matter. So I am atheist almost 10 y now and nothing/nobody was able to change my mind.