Do you think I'm ready to shave my facial hair?

Yo, Im 15 and I am wondering if I'm ready to shave. I want to see how shaving will feel like. I have a growing mustache on my upper lip and Im growing a beard and some sideburns.I also still have a babyface look as well. The only problem is that my parents think I have to wait till I'm "18" to shave. They even claimed that if I shave now, my face will become itchy, I think im actually ready to shave since I don't think it would hurt. Should I just persuade my parents that I'm old enough to shave?