I like them as far as composition, and most have nice tonality. My only complaints are minor technical issues that are easy to solve (poor artistic vision is much harder to solve). As Rod said, the negs were dirty when you printed or scanned them. The grain is weird looking. I've seen some low-quality scanners introduce artifacts into the image that look like that, so it may just be crappy scanning (I'm assuming you're printing in your school's darkroom, so the scans were just to show us your work). A couple seem out of focus; be careful of that.
I'm a high school Literature teacher, despite having been a professional photographer for 20 yrs. I love art and literature, so I got my BFA in photo and my MA in literature and I teach lit. A lot of my students, knowing my background, ask for help on their photo-class work. You're doing pretty well, your work is better than most I see from kids your age. Keep practicing! I still feel after all this time that my work keeps improving; that's true for the best of us.