how to deal with a nasty girl

Here's the deal my bf and I are virgins and in college. We have been dating 3 years, I'm not ready for sex, I get my period way too often, don't want to be on bc again, scared of condoms, fingering hurts, not mentally ready...lots of reasons and overall my bf won't admit it but is scared too. I don't want it to change our relationship so we are just going to wait....maybe it will be better when we have our own place (a year). Regardless of that reasoning my bf lives with his friends. His one friends gf also lives there (she hates me idk why I'm nice met her twice) I know she says made rude comments about me and I let them go but one thing that bothers me is that she keeps bringing up how we haven't had sex and maybe i will give in or how I'm so prude for not ah I got sex with him. My bf has told me this but he hates confrontation so barely speaks up. Can I lie next time I see her and put her in her place? My one friend said to be like "oh honey I hate to make you sound stupid but we don't need your advice on our sex life. Don't be jealous that my man is a lot bigger than yours so I'm sore for awhile after". Is it wrong to say this? Ik I should let it go but I just want to shut her up because it bothers me. Any better suggestions?