Whether it is a naturally occurring color, or something dazzling you have chosen, a hair color can be unflattering.
It could be that people are not necessarily offended by the pink. but if they thought you were quite attractive before the change, they may simply wonder why you did it.
I have seen girls who chose to go goth, and the look was great on them, but some women absolutely should not travel that road.
Your first priority in fashion is to please yourself. Secondly, does it interfere with your professional standards?
If you are happy with the color, but not the reaction, I would advise giving it some time to see if people come around. By the time you have reached your age and school level, you must be able to understand that sudden changes can confuse and upset people. If you are unhappy with the look, by all means, change it back.
Always remember one thing about fashion; no matter how popular a style may seem, if it doesn’t flatter you, you should not do it.
If you choose to keep the pink or not, always wear whatever style you choose with pride and dignity. If you show any sign you are uncomfortable with a chosen look, others will experience discomfort along with you.
Good luck with whatever choice you make.