If time limits were a thing in the main quest of an unfinished story then those comaing Kiyoko's pregnancies for her nine tails would be screwed probably before they even get to the 6th one.
Main quest time limits only work in very certain specific games, this isn't one of them as you will absolutely be forced to focus on the main quest and thus won't actually have time to do the slew of sexual content in the game at the same time because of the few months time limit that's meant to be canon. 2-3 months I think? Which iirc is shorter than TiTS's supposed story '''time-limit'''.
Thankfully, we aren't forced to do the story and can just enjoy the game's sandboxy nature and when we do do the story it's at our own pace. Kas will be waiting in KM for you surprisingly patiently. Plus again, the game is unfinished, to put a time limit on a severely unfinished story, one that doesn't even have an endgame, is dumb.