My 13 yr old had a ruptured appendix, it was awful to see her sick like this. will this cause any problems for her future health?

It might: Sometimes adhesions form between segments of the bowel after this. It might or might not give trouble later in life.

Common problem: Unfortunately, in spite of advances in diagnostic equipment, the frequency of rupture has not declined significantly in decades. After the initial prolonged hospital stay, most will go on to have few issues in the future.Scarring can make some structures stick together & this could complicate future surgery like a c-section or act as a pivot point, trapping bowel & causing cramps or other symptms.