My daughter, who’s 12 years old, lives with me but I signed Form 8332 to let her father take the exemption for her. Can I still file as head of household?

The fact that you don’t claim the exemption for a dependent child does not prevent you from using head of household status on your tax return. As long as you meet the other conditions for this status, including being single and paying more than half the upkeep of the home that is the main home for your child for more than half the year, you can qualify as head of household.