i`m a girl trombone player and i am in the 8th grade but i play with the high school. i have played sence i was 10 and now i am 13 and i a`m first chair out of four seniors guys and that`s pretty awesome, but the only tip i have for you is play sort of loud when you play high notes and sometimes you want slur alot and some times you don`t want to slur at all. and pace yourself unless it is a solo then you can play really loud.
P.S. I have the music to axodintly in love, crazy little thing called love, i`m a belever, enter sandman, radar love, and funky town.
GO HAVE FUN AND MARCH