How to tell over protective mom about boyfriend?

Short story: My mom thinks every male is out to rape me. I've never gotten into trouble in the past for her to assume something bad will happen. How do I tell her about my boyfriend?
Full story:
My mom is overprotective to the point that if I'm even with a group of people in my dorm during the day and there is some guys, she will start lecturing me about safety. I've never went out and did anything reckless for her to think something will happen "again" so to speak. In fact, I didn't go out. Period. I was never allowed to even if it was something as normal as going to the grocery store :/ Now that I'm in college without her leash though, I actually have a decent social life, friends, and my first boyfriend. I've been telling her that he's only my friend, trying to ease her into the idea of a guy existing in my life, but at some point I have to tell her the whole truth. I will want to see him over school breaks. As overprotective as my mom is, probably not. Unless she comes with me >:( Btw I'm 21...