"I banned my 17 year old daughter from buying condoms. Is that okay?"
Taking condoms away from your daughter is like taking armor away from a soldier.
Your daughter is a soldier. She fights off body image issues, acne, period cramps, school stress, and annoying boys.
Though she’s won many of those battles in the past, she will inevitable have her guard down one day. When that day comes, you will want her to have protection.
Condoms are meant to protect good people from harm. Less responsible children would not even bother buying them.
From that, I know you’ve done a wonderful job teaching your daughter to be a responsible teen.
Let her continue this healthy habit into adulthood.