The more I think about it the less I think it'll go this way because it raises a lot of messed up questions (mostly assuming it wasn't a Skylar x Skylar x MC). The only "good" (non self NTRish) way for her and future MC to have banged would be that in that timeline she actually listened to her Mom and cut off contact but then never came to MC house to apologize? If that isn't the case then why would future MC want her? Is Skylar dead? Does Skylar not want to be around future MC anymore?That's also true, despite the NTRish of the whole situation (with yourself ) is that the MC and Skylar's first time with each other wouldn't be at the same moment. Which is weird, among other weird stuff.
That assumes she goes to the future if she goes to to past it has to be within the past few years (due to age of consent stuff ), and more likely a few weeks/months because any further back and you'd start running into issues of MC not knowing her, MC not being a "harem protagonist" yet (how we went from 7 minutes in heaven to having multiple sexual partners his own age, several older than him potentially including his mom) and a bunch of other stuff that would mean MC likely would not be "where" they were at the start of the game. This all assumes that there won't be multiple different run-throughs of the same in game days/that there won't be infinite timelines.