The fact that your daughter worked does not affect your ability to claim her as a dependent. It only matters if she used her money to provide more than half of her own support for the year (if under 24 years of age) or if she made over $4,150 for the year (if not under the age of 24).
You must also qualify to claim her under either the Qualifying Child rules or the Qualifying Relative rules listed below:
Qualifying Child Rules:
Are they related to you? The child can be your son, daughter, stepchild, eligible foster child, brother, sister, half brother, half sister, stepbrother, stepsister, adopted child or an offspring of any of them.
Do they meet the age requirement? Your child must be under age 19 or, if a full-time student, under age 24. There is no age limit if your child is permanently and totally disabled.
Do they live with you? Your child must live with you for more than half the year, but several exceptions apply. Being away at college is one of them.
Do you financially support them? Your child may have a job, but that job cannot provide more than half of her support.
Are you the only person claiming them? This requirement commonly applies to children of divorced parents. Here you must use the “tie breaker rules,” which are found in IRS Publication 501. These rules establish income, parentage and residency requirements for claiming a child.
Qualifying Relative Rules:
Do they live with you? Your relative must live at your residence all year or be on the list of “relatives who do not live with you” in Publication 501. About 30 types of relatives are on this list.
Do they make less than $4,150 in 2018? Your relative cannot have a gross income of more than $4,150 in 2018 and be claimed by you as a dependent.
Do you financially support them? You must provide more than half of your relative’s total support each year.
Are you the only person claiming them? This means you can’t claim the same person twice, once as a qualifying relative and again as a qualifying child. It also means you can’t claim a relative—say a cousin—if someone else, such as his parents, also claim him.
