Throughout your life, you'll encounter people who may not like you the way you are. If it makes you aware of a huge flaw in your character that you've somehow overlooked and that you'd like to correct, by all means, do so. However, if they make you feel bad about something you've been pretty content with already, then the heck with them. Don't change because someone wants you to change to fit their prejudices or petty insecurities. Never compromise yourself to please someone who is not worth it -- and if they expect you to change who you are to be accepted, run like the wind and don't look back.
These scenarios can start so early. They seem to run rampant during junior high and continue during high school, but even in early elementary school you hear the "I won't be your friend if you don't...(fill in the blank)" and in children who haven't yet gotten a handle on handling themselves with confidence, it can be quite hurtful.
Turning you back on someone who pushes you to change or who is downright mean because you might not fit into their clique, isn't an easy thing to do, but it's worth it.