I think I’m just confused but I might have found a plot hole in Spider-Man into the spider verse.

When Miles goes to his first day of school before he got bitten by the spider, Gwen Stacy is there. But then after he got bitten by the spider and the portal opened Gwen got brought to that world apparently. So that means Gwen was there before the portal opened. I might be crazy but this is really confusing me