Welcome to the forum Nankin21!
The Chevy Express has a good reputation and with proper maintenance will go well beyond 100K miles. Just remember that you don't know if it was maintained (you'll have to trust prior owner who may or may not have receipts for everything). Plus, check it over well. It is 16 (maybe 17) years old and it's like buying a a car and house in one.
Just check things out well and let us know how it goes.