Now I'm wondering if I should have claimed my daughter as an exemption

[ChrisJ · Accepted solution]

If you need to make a change, but your return has already been filed and accepted, see here:

If you answer "yes" to all  the following questions, you can claim a qualifying child as a dependent:

1. Are they a U.S. citizen, U.S resident, U.S national, or a resident of Canada or Mexico?
2. You can't claim someone who is married and files a joint return with their spouse, takes a personal exemption for themselves or claims another dependent on their own tax forms. Are you the only person claiming this dependent?
3. Are they your son, daughter, eligible foster child, brother, sister, half brother, half sister, stepbrother, stepsister, adopted child or an offspring of any of them?
4. Are they under age 19 or, if a full-time student, under 24? (No age limit for disabled children)
5. Did you provide more than half of their financial support?
6. Did they live with you for more than half the year?

Exceptions may apply. If you don't see your situation addressed or want to learn more about a question, a comprehensive guide to claiming a dependent can be found here. You can also refer to IRS Publication 501.