I don't think there's an issue having your parents know you visit the gynecologist regularly, especially since it is essential to women's health. regarding them knowing if you're active or not, that depends on the relationship. some parents don't mind and stress safety, others get REALLY angry because of the conservative, traditional mindset that sex should be saved for marriage.
I don't know if that's normal, but I looked up your situation and this page shows a lot of women having the same issue, so it's not uncommon, which is a good thing.

The main question is: HAVE YOU HAD YOUR PERIOD?