I'm 15 only had a menstrual cycle since 14 and I'm late but a total virgin?

I don't count my days to know the day I'm suppose to get it, so I wouldn't know. I'm actually terrified but I don't understand I'm a a virgin never been penetrated or anything In that matter, it's june 29 Nd I usually get it the 20-26 of a month., the first month I started track it was late and that was April 30 Its been regular since then on the dates I expect it.. I finger myself but I don't have nails? I'm afraid to tell my mom because she would guess I'm pregnant but Im not.?!!! I think I'm sick from the weather changing but yet again I'm a virgin Can SOMEONE PLEASE HELP ME!!!!