Claim dependent

If she is under the age of 24 and a full time student then her income is not a factor.  Only if she provides over one-half of her own support becomes a factor under the Qualify Child rules.

You can claim her as a dependent if she meets all requirements under the 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.

• Relationship test. The child must be your son, daughter, stepchild, foster child, brother, sister, stepbrother, stepsister, half brother, half sister, or a descendant of any of these, such as your grandchild, niece, or nephew
• Residency test. The child must have lived with you for more than half of the year. Time away at school still counts as living with you.
• Age test. The child must be:
  • Under age 19 at the end of the year and younger than you (or your spouse if MFJ), or
  • Under age 24 at the end of the year, a full-time student for some part of each of any five calendar months during the year, and younger than you (or your spouse if MFJ), or
  • Permanently and totally disabled at any time during the year,
    regardless of age.
• Support test. The child cannot have provided over half of her own support during the year.

In your case, it sounds like there are only two areas to be concerned about:

1. The age test, but as long as she's in school full time for some part of each of any five calendar months, she'll qualify.
2. The support test, but education expenses are considered part of support, so if you're paying the substantial education expenses you indicated, you should be covered there also.