what momma doesn't know won't hurt her right?

So I'm 19 and In college, I have a boyfriend and we've been having protected sex (birth control pills, condom, and pulling out w/ condom) I've been on the pill about 3 years now because of my irregular periods! I tell my mom everything but she told me to be smart and not to sleep with my boyfriend until I finish my school!..... how should I tell her I'm sexually active or should I just not??