Liking wedgies is not normal, it's a rather unusual thing you liking them as most people are usually given wedgies as most people that give wedgies are bullies.
Were you a victim of something similar? Maybe that's the reason you like what you like.
Speak to your mom if you feel you need support, but be careful she might be surprised by this.
What do you like about wedgies, is it a physical thing? There are other ways of getting off you know