Are you allowed to go to your old high school (that you never got to graduate from, and to this day you wish you did) to go inside and look around to relive the memories?

I think I heard somewhere that some don’t allow you to. I was in 9th and 10th grade in this school, and it was amazing. I made the best friends, got to experience the acting lifestyle, and other things. Then I moved away, and the high school I finished in was a hellhole comparatively. I still want to rewind and finish school at my old high school.