Graduate student and residency for tax purposes

My child was a graduate student in Maryland and turned 24 last year so she files as independent this year. We lived in California and then moved to NJ last year. My daughter got a Maryland drivers license, voted in Maryland  and registered her car with her Maryland off campus address in 2019 and also claimed part time resident in Maryland for part of 2019 but had no income in 2019 in Maryland. 

In 2020, she worked part time and made a small amount of income.  She graduates in 2021, and doesnt intent to remain in Maryland.

Does she file as California/NJ resident like us since she was a full time student, or does she file as a Maryland resident since she had a Maryland drivers license and voted there?