@Lipop There are three different issues in your post.
1. "This year my income is above the threshold and wont be claiming her as a dependent".
Your income is not too high for her to be your dependent, but is probably too high for you to claim the American Opportunity Credit (AOC).
2. She also has an income of $24k and has lived away for more then a year.
That means she cannot be your dependent. But that assumes she was really living away. Being away, from the parent's home, for the sole purpose of attending school is only a temporary absence and she is still considered as living at home. In that case her $24K would have to be more than the tuition you paid, for her to be a non dependent.
3. Even if she is an independent there is another requirement for the AOC. A full time, unmarried student, under age 24, even if you don't qualify as a dependent, is only eligible for the refundable portion of the American Opportunity Credit if he supports himself by working (earned income). You cannot be supporting yourself on parental support, 529 plans or student loans & grants.
