Most Helpful Guys
Unless directly against your school policy this shirt is fine. Anyone who tells you it sends the "wrong" message, or give boys an excuse needs to realise opinions like that are part of the problem. Women don't dress wrong. Men and boys are brought up to think wrong.
Most Helpful Girls
Probably depends how you wear it~ if you wear very modest clothes on your lower half and not show off any bare skin on your legs, then it might be ok. However if you worse that top with short shorts or a mini skirt then that would be inappropriate.
You're shirt says "look at my boobs"
The dudes are gonna have the wrong idea, and for freaks sake. You're in 8th grade. Even tho you look older, you might need to change your closet.
But hey, you are really pretty. Like really really pretty.