Make choices that are best for you and only you, and let others live their own lives. You can't make anyone "do" anything, but you sure can make yourself do anything.
You sound like a solid young woman with a good head on her shoulders who has witnessed some traumas. See if you can find a teen support group (like Alateen but there are others) and maybe talk with your school counselor for some referrals.
Take good care, the rest of your life is waiting.