To be claimed as a dependant, your daughter should have an income of less than $3100 per year or be a full time student for at least 5 months of the year.
If she's not a student and she makes this much, you cannot get an exemption for her.
Let me know if you have more questions.
If she is under the age of 19 then the gross income limit does not apply.
There are two exceptions to the gross income test. If your child is under age 19 at the end of the year, or is a full–time student under the age of 24 at the end of the year, the gross income test does not apply.
So, if she was under the age of 19 at the end of 2004, you can claim her as a dependant no matter how much money she made.
She will also file her own taxes but needs to mark the box on her return that says that she is a dependant for someone else.
Let me know if you still don't understand.