Katie, based on what you have said, it sounds like your sister could be jealous of your life. You were able to go away to school and she wasn't. To her you might have a more interesting life. Sometimes we will look at others' lives and wish we could have what they have.
Whatever you decide to do, be careful. This could be a no win situation.
You might talk to your mom about what happened, she might be a little more accepting than your sister, if this is what you are looking for.
Good luck.