I need other’s opinions

So I’ve been with my girlfriend for 6 months now, And we haven’t even sh@gged yet, the most we’ve ever done is kiss, It doesn’t help that we both are usually really busy working so we don’t have alot of time for each other and when we do she has to care for her sister but we do see each other once or twice a week at the moment but we will see each other more soon but besides whenever I’ve tryed suggesting her to stay over she just says “I think we should wait” which I respect but I just don’t get it, she says she’s lost her virginity but there’s no proof and all her friends have told me that she hasn’t lost her virginity which makes me think the reason why she is so frigid in that sense, like she won’t do anything with me but will with random lads on one night stands, that’s what’s frustrating me and the fact that the majority of my friends say that it’s weird that we haven’t done anything yet, I personally don’t know what to think about it I haven’t had this problem with any other girl, as much as it annoys me she tops every other relationship I’ve had and iam the happiest I’ve ever been but iam just abit stuck on what to do and how to approach the situation, any help would be greatly appreciated.

Iam not complaining at all I’d happily wait till she’s ready, I’ve told her that I genuinely just want her to stay over and I’ve said I don’t want us to do anything just so she can get use to the fact of staying over, but she says that’s she’s not ready or that we should wait which I’ve told her is fine, but if that’s the case I’d happily wait, whenever we have spoke about it she never really wants to tell me why she’s not ready or why she wants to wait, so I don’t force her to tell me and just tell her it’s ok if she doesn’t want to tell me…