Graduate School Student & Multiple States

I have a child (no longer a dependent to me) from Illinois that attended a grad. school in Maryland since August of 2018.  She graduated in May of 2020 and was unemployed until she started a full time job in late July of 2020.  She started paying rent on an apartment in Washington DC on July 1, 2020, but did not move in until July 14th when her Maryland grad school's apartment contact ended.  I am planning on filing her state taxes as a full time resident for Illinois and then as a non-resident for Maryland and Washington DC.  The basis is that she was a student / unemployed for over 183 days, lived in her DC apartment for 170 days, and she has not changed her residency from Illinois (still has an Illinois driver license) to Washington DC.  Is this correct?