If she's okay socially, then she'll be fine on that front. Just be prepared that colleges are usually designed to give the students far more responsibility for their own learning, and tend to expect them to do their own reading around the subject and so on. They also do less spoon feeding. Whilst this is much better preparation for university / life, some students struggle with the maturity that is required to do this, and have a bit too much of a good time in their social lives! It is worth keeping an eye to make sure she keeps a balance between these things. IME, this is the problem that we most commonly occur with our students, they enjoy college life a bit too much and don't put quite enough effort into their work sometimes!
The other tip I would give is that if she runs into any problems, she should try to deal with the problems early. The responsibility is with her to speak up and say something to her form tutor / class tutor is something is not going right. Again, IME tutors will do everything they can if they know there is a problem, but they tend to rely on the students telling them about the problems in the first place. I think that is probably one of the most important pieces of advice I impress on my students. So, if she does not enjoy a subject - get her to deal with it early, most subjects can be changed within the first four weeks or so, but she needs to speak up if she has got any doubts or worries. The worst situation is when the student doesn't say anything, but just stops attending class. If there's a problem, she will need to speak up as it is not like school. We assume that everything is going okay unless they tell us otherwise.
I went to a sixth form college (the same one I now teach at) and I think it was much better than school as it was an excellent stepping stone to university, but she/you musn't expect it to be like school - the responsibility is now with your DD to manage her own learning (with your support). Some students are not mature enough for this level of responsibility, and if your DD is like this, then speak to her form tutor as additional support can be given (for example, I had one student like this and we agreed that I would email his mum if I felt he was slacking too much! but over time he learnt to manage his own learning and has just left with 2 A grades). But it is down to the student / parent to instigate this.