Did she have any scholarships, grants, or other income of her own of any type in 2016?

You say she turned 24 "this year". Most likely, you'll lose out since her age will not be under the age of 24 on Dec 31, 2016. If her earnings in 2016 are more than $4K, that nixes it.

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 relationship test and a residence test. Only a QC qualifies the taxpayer for the Earned Income Credit. They are interrelated but the rules are different for each.

Since she is over 23, she can no longer be your QC, even if she is a full time student.

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 the taxpayer ALL year

2. His/her gross taxable income for the year must be less than $4,050 (2016). This includes taxable scholarships

3. The taxpayer must have provided more than 1/2 his support. Scholarships and loans are support not provided by you (unless you are legally obligated for the loan, such as a co-signer)

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