School/Graduation Question (Steve)

So I know that Steve is a year above Nancy and Robin. Because he says that if he doesn’t go to college he can be around for Nancy’s senior year in season 2. I’m assuming that he graduated in the summer before the events of season 3 (8 months after as it was October in season 2) before he started working in scoops ahoy.

Which would mean that Robin would be going into her senior year after that summer and would be graduating in the summer of 86’. So how is it that Steve and Robin would have been in the same class? (Mrs Click’s class). Steve said that he didn’t pass that class but it’s never mentioned that he got held back for any reason the same way Eddie did. He didn’t get the grades for college but he still graduated because the girl he goes to the basketball game confirms that.

I’m British so I know our schooling system is a little difference but you guys don’t mix school years/classes that way as far as I know? Or maybe I’m wrong!