we don't know anything about the GF but if either parent can claim her as a qualifying child (QC), then that ranks higher than qualifying relative and you do not get to claim her. even if the parents choose not to claim her if she's their QC you don't get her. here are the rules for the parents
Qualifying child
1) Same principal abode as the taxpayer for more than ½ the tax year. Temporary absences like
for school are ignored
2) If not a full-time student, under 19 at the end of the tax year. If a full-time student under 24 at end of tax year.
Full-time means an individual who during each of 5 calendar months during the calendar year in which the taxable year of the taxpayer begins is a full-time student at an educational organization described in section 170(b)(1)(A)(ii), or is pursuing a full-time course of institutional on-farm training under the supervision of an accredited agent of an educational organization described in or of a State or political subdivision of a State.
3) Hasn’t provided over ½ his/her own support
4) A US citizen, resident alien or national, or a resident of Canada or Mexico
