Confused hurt and alone

Ok so I’ve been talking to this guy for about 4 months now and we just recently started dating. I really like him and am considering having sex with him (I’m still a virgin) but my family is not open to talk about those kinds of things nor would I feel comfortable talking about them because I feel like they would judge me. On top of that, my younger sister overheard my conversation with one of my close guys friends that asked if we had sex to which I responded “not yet.” She’s the type of person to get mad easily and is now pissed at me because she’s feels I don’t value myself or my body which is totally untrue. She continued to talk down to me about it and I just feel so alone because I feel like maybe it is too early but I also hate being treated like that I told her it is my body and my choice and she’s still mad and thinks I’m dumb. I feel like I have nobody to talk to about it (certainly not my family members) and I’m sick of feeling like I have to conform and wait to have sex when I know it’s something I should do when I feel ready. . I guess my question is what should I do and how should I approach the situation?