I was a 3 time college programmer from 1998 to 2000. I was DAK opening crew at the TOL, I was a Backlot tour guide and then did an advanced internship as a stage technician.
Its absolutely a fantastic opportunity and something I would highly recommend to any college student. It was a fantastic time and has also been great on my resume, helping me in getting a job or two.
That being said, I would not let her go as a freshman or sophomore. I was 20 on my first one and while I loved my time there, I think I got more out of the program when I was older. You are talking about a TON of college kids, living together and really not having to worry about going to class except once every couple of weeks. If you remember back to college and the party environment it is, you can imagine what its like when you don't have to worry about studying and grades. I would recommend 21 myself, but at least 20... Personally, and I say this as a father, I think it will be easier to handle the environment at an older age than at 18 or 19. Just personal opinion, but an opinion from someone who experienced the environment.
Please don't let that scare you... the College Program is a FANTASTIC opportunity... in my experience, older students took better advantage of the opportunities it presented such as advanced internships, shadowing, networking, etc.
Either way, I do highly recommend it... although one other little caveat... it can increase ones Disney obsession, driving one to go down yearly or more and purchase DVC timeshare points ;-) Just a small warning... lol