18 and permission

Okay guys. So im 18 and i LIVE with my mom. But every time i want to go out i have to ask her for permission. Tomorrow i have a date and im scared she's going to say no. but i dont want to miss it. 😭 im 18 already, but i feel bad not following her rules. ughh what do i do just in case she says "no"? i want to tell her that im 18 and that i know whats right and wrong and that i should be able to do what i want, but since i live with her i dont know if that is right from me