Our daughter has always been extremely shy. She is hilarious once you get to know her. She has always been into quiet activities and I swear her whole goal in life is to be unnoticed.
She has never had more than a few friends and even then they change from year to year. She always stayed friendly with them, but they were not bosom buddies. There was another mom with a daughter like ours. We got together every once in a while and helped plan, "Game nights" to include only a few extra friends to come over for pizza and games. These group get togethers became a little larger each year and for Prom, there was a very large group of friends that went as a group to Prom. We hosted a fancy dinner and then they all rode together to the event..
Our daughter was never bullied, she was just more mature than a lot of other girls and did not enjoy what they all enjoyed. She likes art, it is her passion. She is addicted to books, she always has 3 going on all at once with extras waiting to be read, just in case she devours all of them at once.
In middle school she did not want to take PE at the school, instead she wanted to take extra academic classes so she on her own, decided to take up rowing. This was her choice. For 6 years she took these after school classes and it was not until her Senior year in high school, she wanted to actually compete! She came in 2nd place in her first competition and it was a National Competition!
She is now in College and it is Nirvana to her.. The other people that she is now friends with are like her. They are smart, funny and nerdy.. Very mature and take their studies very seriously.
Let your daughter be her own person. Let her know it is good to be her own person. See if she can figure out where her interest lies. Art, music, dance, design, community service.. And allow HER to lead you. It is not fair to her or her team mates that she does not want to participate. If SHE chooses to do something and THEN does not want to participate, that is a different story, she then needs to follow through.
Guide her with information and opportunities, but allow her to be in charge of the choices.