Your marital status, for 2017, for tax purposes, is determined as of 12-31-17. If your are divorced or have a legal separation on or before 12-31-17, you are single for tax purposes.
But your marital status does not prevent you mother from claiming you. Even if you are married on 12-31-17, she can still claim you (assuming she meets the other rules) so long as you don't file a joint return with your spouse. That means, if you are married, he will have to file as Married filing separately (MFS). If you need to file, so any reason, you too will have to file as MFS.
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There
are two types of dependents, "Qualifying Children"(QC) and standard ("Qualifying
Relative" in IRS parlance even though they don't have to actually be
related). There is no income limit for a QC but there is an age limit.
A child of a taxpayer can still be a “Qualifying Child” (QC) dependent, regardless of his/her income, if:
1. He is under age 19, or under 24
if a full time student for at least 5 months of the year, or is totally &
permanently disabled
2. He did not provide more than 1/2 his own support. Scholarships are
considered third party support and not as support provided by the student.
3. He lived with the parent
(including temporary absences such as away at school) for more than half
the year
A person can still be a Qualifying
relative dependent, if not a Qualifying Child, if he meets the 6 tests for
claiming a dependent:
1. Closely Related OR live
with you ALL year
2. His/her gross taxable income for the year must be less than $4,000 (2015)
3. You must have provided
more than 1/2 his support
In either case:
4. He must be a US citizen or resident of the US, Canada
or Mexico
5. He must not file a joint
return with his spouse or be claiming a dependent of his own
6. He must not be the
qualifying child of another taxpayer
