Several items involved here:
- If you file jointly with your husband, no one else can claim you as a dependent. If you do this and your mother claims you as a dependent, it is likely that this will be flagged by the IRS. (exception is if you are filing jointly to obtain a refund)
- You seem to meet the IRS definition of student -- The IRS defines full-time student as one who is enrolled as a fulltime student during part of five months of a year.
- What is questionable in your data is whether you provided more than half of your support. Tuition does not count.
- The tax reform act diminished the value of an exemption (like the dependent exemption) and increased the standard deduction amount that taxpayers can claim. Is it possible your mother is thinking about the value of an exemption pre- tax reform?
Here is an interesting link that might help you ... it is an interactive interview at the IRS site to walk through questions regarding dependency: https://www.irs.gov/help/ita/whom-may-i-claim-as-a-dependent
Not sure what your relationship is with your mother (assume it is OK since you are living at her house), but if your mother can claim you as a dependent doesn't mean she has to. I would suggest looking at your taxes using different allowable scenarios and see if in fact your mother would be losing big on not claiming you and figure out a middle ground to minimize your taxes in total. Put another way (example only), her saving $2000 on taxes doesn't make a lot of sense if you are paying $5000 more and vice-versa.
