Why can't I get any stimulation from touching myself?

Hello! I'm a 17 y/o female and I came to ask... Why I can't get any stimulation from touching myself. :<

Honestly, it makes me a little jealous to hear about all the people who reach orgasms every time they masturbate, while I'm over here getting absolutely nothing from it. I'm certain there's nothing wrong with me, as I've had a friend touch me and it works real well; but I can't to that point myself.

I can't get toys since I still live with a parent (and I'm sure she wouldn't approve), and imagining doesn't work. I've tried using a toothbrush. Nothing.

My problem is I get turned on quite often and randomly, and it makes me crazy 'cause I can't do anything about it. What can I do?