Well, we know L&P isn't specific, especially not enough to say "Aiden will finger Sophia in the back of the classroom", let alone be one of the animations, so we can tell you're just wildly guessing in the hope all this wait will be worth it.
If anyone will be fingering Sophia, it'll be Ellie in the shower, but even that wouldn't be likely until PD16. I'm guessing the next step before that will be Sophia fingering herself in the shower on PD14, but in front of Ellie. After all, she was groping Sophia's boobs before Aiden got the chance, because that's the way progression works in this game.