I thought my husband's family (five kids) handled this one very well when my husband was a teenager. Curfew, very simply, is set based on maturity and responsiblity, not age. If a child is mature and responsible and can handle a late (or non-existent) curfew, then that's what he/she has. If a child does not show maturity or responsibility, then there is a strict curfew.
For example, my sister-in-law, three years older than my husband, lived at home until she was 20 and ALWAYS had an 11pm curfew because she could never make it home on time, crashed the car, and showed little responsibility unless it was school. My husband, on the other hand, was curfew free by 17 because he had shown he could meet curfew, handled all his responsibilities well and had generally shown he knew how to make good decisions when out and about.
My mom handled it similarly. My curfew in high school depended entirely on what I was doing and who I was doing it with. For example, I worked at an ice cream parlor my senior year that closed at midnight, then we had to clean the store. My curfew was 3:30am because my co-workers and I would go to an all night pancake house for "breakfast" and unwind after work. When I started dating my husband, and hanging out with him after work, my curfew was cut back (severely) to one hour past clocking out...and my mom would call and check. I was pretty darn mad at my mom for that one, but I understand why.
It may be time for a family meeting to set the "guidelines" for curfew with the disparate ages and maturity levels in your household. Remind everyone that as long as they live under your roof, your rules apply, and age is NOT the determining factor. Responsiblity and maturity are. If your daughter wants later curfews, she will act accordingly and that includes accepting that there are limits on what a 17 year old girl can safely do in this world.
I would also call local law enforcement and see if there are any local curfews for high schoolers in your area.
Hope this helps. Good luck! I've taught high school for 17 years and this is a sticky issue. But, most parents do a good job and it's only after the fact that students "get it." Safety first.