Tell her that you don’t feel that you will be able to learn how to survive in the real world if you always have her to fall back on. It’s going to be hard for her because you’re her baby, but she should understand. How far away did she go from her parents for school? Remind her of how it felt for her to finally be able to live on her own and tell her that you want the same kind of feeling.

Maybe you guys can arrange a schedule where you’ll come home for a few weekends a month. Start by coming home more often, and then make it less and less until she doesn’t mind you being gone so much.

Just out of curiosity, how are you going to get in-state tuition for Washington State if you live in Arizona? You have to have lived in that state for at least a year to get the in-state tuition costs, and going to school there doesn’t count for that time.