Not just yet.
This is is pretty good question.
I don't think it will be implemented, since most of the content involves sex. I mean, the design implies that the mc penetrates the female characters at least once and then does anal training.
You can do it with secondary characters, like the future other nuns, yes. But they will be treated as secondary characters.
I honestly like your idea, so much so that I would make a character like that, but possibly for another game.
Personally, like RPG or stealth games, l love subverting expectations(or not following tropes). Like doing a pacifist run and the story or NPCs react to your surprising behaviour(throughout the whole game, not just once) and the game does change a bit. Or, i always imagine situations where games want you to kill or do something, but you do the opposite of that, or find your own ways to do it. And the game acknowledges that.
As for sex; i always loved female protagonists being you. Having full control of them, when to undress, to move around naked and people noticing you and you choosing what intimate,sex action you want. I remember playing Artificial Academy 2 and the reactions of the girls when you have anal sex before vaginal. Each personality there has a unique reaction according to their personality. If you offer sex again while they are virgin, they will comment when you will take their virginity or if their fetish is anal sex(from character editor), they will be joyful.
I also liked in that game, you can put a module, that makes every girl after vaginal sex, to always regain her virginity back. For a fantasy setting, one could make a character that enjoys the pain or the action of first time sex again and again, or maybe else.
It is all immersion and player agency what i am trying to say.
I am sure it is possible to do it through one character due needing to present your story as you want. But having the choice to keep virginity is sure something tasty. Long term reward for short term pain(or patience).
It sure does more interesting for a girl that loves to have fun or intimate with a person she loves but keeps the virginity until marriage. It does require willpower for her and the other party. And the implications behind this concept really does fire lot of things.
It could work on the nun or someone else who favors their religion, (vaginal) sex after marriage.
In the end, it is all up to you. i was just asking. But if you do that concept, i will be very happy that at least, one time, my suggestion was heard