School showers are so awkward!
at some point during my school year teachers started complaining about how students smelled bad after gym class. My gym class ( girls) was forced to shower after class. Since there's only 5 shower heads, we had to stand in a line, butt ass naked. Some girls didn't care if they were seen in the nude, but for me , there is nothing more embarassing than standing in a line butt ass naked in front of a bunch of girls you know. I had to cover my boobs and vagina with my hands and i just acknowledged the fact that my naked butt was going to be seen. The other part that i hate is having to undress and redress after, because i cant cover up as well while doing that, so every once in a while a girl walks by and gets a glimpse of my boobs hanging out.
I'm not exactly sure if you are looking for advice here, or just wanted to talk about how this is embarrassing to you. While the picture you paint certainly does not sound like a bad one to a guy such as myself (immature lols.), I will remember that you are in middle/high school and talking about school-aged people and empathize with how embarrassing this must be for you.
I was fortunate when I was in middle school and high school, because this sort of thing wasn't enforced then. I wouldn't even so much as take my shirt off around other guys because I was self-conscious about how I looked. Usually I would change in the bathroom stalls. I imagine it wouldn't have been pleasant standing in line with a bunch of other naked dudes, especially the immature guys I went to school with. You actually seem to be handling this better than I would have - I might have caused a scene to avoid stripping among peers.
Do you think you're feeling shame about your body, or is it only the discomfort of the lack of your personal privacy?
Just keep in mind that the other girls are probably as embarrassed as you are, and you won't have to do this forever - eventually you'll be out of school or else they'll do away with the mandatory showers.