This is just how I'm reading the situation, so take it with a grain of salt, but I'd say it seems like a pretty safe bet that both Abby and Sasha are virgins. Both of them have way too much of a "good girl" vibe for it to really make sense. In Sasha's case, I did consider that she could be a victim of SA, but I don't see it really fitting the tone of the game or how quickly she perked up after meeting MC. At the very least, I would be really disappointed if she were. I think making a LI a survivor of SA is a pretty overdone trope that seldom adds anything worthwhile to a character that couldn't be gained from some other kind of trauma (in Sasha's case specifically, I think her parent's dying and then being neglected and ultimately abandoned by her relatives is more than enough to give her backstory depth and a place to grow from, adding SA would be wholly unnecessary)
As far as the others go:
-Ellie and Mallory are 100% obvious virgins
-Kana and April are like 90-99% certainty based on what Kana says about boys being intimidated by her and based on Billie saying that all April does is read and watch TV
-Juniper is like 85+% certainty based on how she interacts with her mom and how she hides her true self behind what is essentially a classic tsundere exterior
-Billie is hard to gauge at this point, based on the fact that she is a streamer, I'd say that she is probably just a tease and hasn't really done anything, but I can't quantify my level of certainty
-If any of the students aren't virgins, Lana has to be at the top of the list since she's literally the only one who even kind of has a boyfriend
-Lily and Risa are complete enigmas and I honestly have no idea whatsoever, although I'd say that Lily is more likely to be a virgin than Risa, if only because she seems to be a good natured, heroic character
