Do I have to claim my 21 year old full time college student as a dependent ?

Hi, 

 I have a couple of questions regarding to how classify my 21 year old full time student.  She is living off campus for the entire year but  away from our  home.  Turbo tax qualifies the student as still considered living at home even though student is away at college. Is that correct?  Then later on in  the CA state return, it asked what is the principal residence information if it differs from the permanent address (she has the temporary address at college which differs from her permanent address).

 

1. Why are they asking for that?

 2. Do I enter the address she is living at during school?

 3. If I do that, will all her tax correspondence  go to this college address?

  Not sure how to answer this part.

On another line of question, it seems Turbo Tax automatically  reclassified my daughter's  status to single/ and not able to be  claimed as a dependent on anyone's return.  I don't qualify for any of the education credit so would I need to claim her as a dependent on the return?  I do support her more than 1/2 financially so not sure for my tax return if I should claim her as dependent or not. Hope you can advise and thanks in advance