Q. When does it stop that I can't claim her as a full time student working part time?
A. The year she turns 24 or stops being a Full Time student (if her total time, as a full time student is less than parts of 5 calendar months). For example, being a full time student from any day in January to any day in May (even May 1st) counts as being a full time student for 5 months. It does not matter how much money she made.
There are two types of dependents, "Qualifying Children"(QC) and Other ("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, student status, a relationship test and residence test. Only a QC qualifies a taxpayer for the Earned Income Credit. They are interrelated but the rules are different for each.
The support test is different for each type. The support test, for a QC, is only that the child didn't provide more than half his own support. The support test for a Qualifying Relative is that the taxpayer provided more than half the relative's support.
See full dependent rules, see the other reply or at: https://turbotax.intuit.com/tax-tools/tax-tips/Family/Rules-for-Claiming-a-Dependent-on-Your-Tax-Ret...
