How to deal with a friend that doesn't go on roller coasters?

on Thursday me and my family are going to six flags and my parents won't go on many roller coasters and i usually bring friends who have the same sick obsession with roller coasters so we have no problems. but this year i am bringing this girl who i JUST found out is really really scared of roller coasters . i cant cancel because it is already set up with her parents. what can i do ? I don't want her to ruin my vacation by being a wimp :( I love her to death, and she is my best friend, but SERIOUSLY .