There are 2 issues.
1. Who can claim her? The parent that she lived with more nights is the one who can claim her. Nights at school would be considered as divided equally between you and your ex. If you can’t agree on that, the parent with the higher AGI gets to claim her.
2 Should she file independent of you. The law is that if you CAN claim her she must say that on her return. So she really can’t file independently. By claiming her you get tax advantages like filing as head of household if you are unmarried, other child tax credit, and earned income credit if otherwise qualified.
