i have 2 questions
one: do the events/quests in this game have time limits like if i dont do them they will disappear?
two :how long does it take to beat the game?
btw when i go to the gallery for the girl named sheila the game gives some errors
No, there are no events you can miss.
Depends on how you play. It can be anywhere from 2-10 hours. It really depends on if you use skip, auto, or if not what pace you read and advance the scenes at.
That's only before you get her lewd, which just came out in this version. Once its unlocked the error no longer appears, and it will be fixed in 0.56.