Alright, let's see. Perhaps you can start with listing a few memories of your first year at high school. You know 'nervous feelings, butterflies, sweaty palms.' etc. So begin with walking into the big school and all your fears clouding your mind. And then a brief mention of the teachers, lessons and homework. Perhaps it was a very BAD day however a little bit of sunshine managed to find it's way, such as: meeting your best friend for the first time. If you honestly can't remember anything, then just make up obvious stuff (I do that loads of times, lol.) Oh and also, remember not every poem rhymes so don't worry about that.
Need more help, just pm me. 
