The idiom "changed my mind" means "I thought one thing; now I think another". It's normally used for one specific (often trivial) thing at a time. You always "change your mind" about something.
A: I thought you were having vanilla ice cream?
B: I've changed my mind. I'm having chocolate.
A better way of saying what you want is "it changed my way of thinking / it changed a lot of my ideas / it challenged much of my previous thinking ... "