I don't really care whether or not a female MC is a virgin - but I do require them to have agency.
And by agency, I mean player agency, not character agency.
In other words, I prefer the player have the power to approve or deny any and every relationship. If you throw a love interest at me, I want the ability to either accept them as a potential partner or refuse them because I'm not interested (for whatever reason). I'm very much not a fan of scenarios where the main character automatically fawns over someone I have absolutely no desire to interact with. Or automatically hooks up with someone I want to avoid. Or willingly chooses to share or otherwise bring extra people into a relationship without asking me. I think that, even in porn games, players should have the power to choose which LIs they want to interact with, and which kinks/fetishes they want to engage in and which ones they want to avoid.
So in a way that can imply virginity - I don't want a game constantly talking about past relationships or otherwise have exes constantly show up (in the same vein, I'm not a fan of games that start you out in a relationship and basically require you to either break up or cheat). Especially for female characters (where I definitely don't want the game to assume past hetero relationships if I want them to be lesbian). I like the ability to decide for myself who the character is when the game starts. The easiest way to do that is to just never really mention past relationships at all, while a more interactive option might be to have the game ask you when you start whether or not you want the character to have been in relationships before (and if so, is the character straight/gay/bi/etc).
None of this is technically exclusive to female MCs, though. I prefer the same degree of agency for male MCs as well. I just tend to be slightly more annoyed when games make forced decisions for female MCs than I am when they do for male MCs.
In the same vein though, I tend to avoid female MC corruption games like the plague. Mainly because they are almost always the exact opposite of the MC having agency, and generally just turn into the player watching the MC constantly getting abused or coerced into stuff against their will until they're broken. I won't fault people for being into that sort of thing, but it's not something I've ever really found all that interesting or worthwhile.
Part of it is a question of how you view MCs, honestly. Some players see them as the main character in a story someone else is telling, and some people tend to put themselves into the MC role (especially because you're being asked to make choices to make decisions for them, making you role more active than simply passively watching a film or reading a book). Whenever I play games, I tend to want to be able to shape the MC myself, and not just passively follow along with someone else's story.