Knock her up. Marry her. Don't ask her if you can... Just do. Lol
Vail and northstar both have plenty of terrain. You will be fine with the intermediate and beginner stuff here. Both have beginner parks. You can also go to plenty of restaurants and shit without issue, they will absolutely card you though so no drinking foe you. Only true bars don't let people under 21 in after like 10 pm. I'm guessing you will be too tired though. Vail is way bigger and has a lot more stuff around within close proximity so you won't have to drive anywhere once your here.
I live in vail and have been to northstar like 4 times now.