My younger son wanted to take a gap year very badly. To him, it meant living at home, rent free, and racing. We said, fine, but you have to get a job of some kind and defer your admission one year, no waiting to apply. We also said he could do City Year (your daughter might like this, it's basically Teach for America without a degree), go to Israel and do volunteer work, or work as a teacher's aide, as he had done this in HS. He turned his nose up at our suggestions, so off he went to U of A. He came home in May with good grades and promptly enlisted in the Marines. He is getting out in March and has essentially had his 9 year Gap year! At 27, he is going back to school as a second semester sophomore.
In retrospect, we should have given him a little more leeway. It was not usual for kids around here to take a year off and I was frantic he would never go to college. While he was an excellent student and graduated HS with a full semester's worth of college credits, he's always marched to the beat of a different drummer. He was close to leaving the military a couple of times in the past 9 years, but he got really huge bonuses for staying, so he stayed. He also had the opportunity to go to the Naval Academy or do a college completion program for NCOs and keep his rank and pay while in school. He turned both down and said he had to do it "his way." So, he's set for $, has tons of investments and his education is paid for. His wife is in her junior year at Cal State Long Beach and I think her influence was a lot stronger than mine.
I haven't changed my mind about the necessity of a college education, but I am pretty sure I would have handled him staying home and racing for a year a lot better than I handled him enlisting. I guess what I am saying, is listen to your daughter and set some boundaries at the same time.