Run this IRS app
https://www.irs.gov/help/ita/whom-may-i-claim-as-a-dependent
Yes, you can claim your daughter as your dependent as long as she did not provide more than half of her support. See all qualifying rules in this FAQ.
See also What does "financially support another person" mean? for reference.
You can claim her as a dependent if she did not provide over one-half of her own support under the Qualifying Child rules.
To be a Qualifying Child -
1. The child must be your son, daughter, stepchild, foster child, brother, sister, half brother, half sister, stepbrother, stepsister, or a descendant of any of them.
2. The child must be (a) under age 19 at the end of the year, (b) under age 24 at the end of the year and a full-time student or (c) any age and permanently and totally disabled.
3. The child must have lived with you for more than half of the year. Temporary absences while away at college are considered living with you.
4. The child must not have provided more than half of his or her own support for the year.
5. If the child meets the rules to be a qualifying child of more than one person, you must be the person entitled to claim the child as a qualifying child.
6. The child must be a U.S. citizen or U.S., Canada or Mexico resident for some portion of the year.
7. The child must be younger than you unless disabled.
You've already received some great replies--I just wanted to add a side note.
The best thing your daughter can do is to open a Roth IRA. If she continues to contribute to it each year she'll easily retire as a millionaire TAX FREE. What could be better than having a couple million bucks with no taxes? Seriously, you've gotta check into this for her. TAX FREE retirement!