Welcome to CC!
This is so tough and I’m sorry you’re going through it. 
A couple of things, kids definitely can get scared and start to freak out about now and that is totally normal. The best you can do is try to be supportive.
I realize that’s hard when you feel shut out of the conversation. Are you paying for college? If so, I’d simply let her know that as a stakeholder in the decision you need to be able to talk to her about what she is thinking, without judgement.
I recommend picking an activity you both like doing together and a time that gives you some space (not right after school or before bed) and giving it a go then.
The process of separating can be bumpy…hang in there! 