You either qualify to claim your daughter for the year, or you do not qualify. A year isn't broken into parts, so the 6 months that she didn't work don't mean much.
Was your daughter a full-time student for 5 or more months during the year?
If not, did she make more than $4,050 for the whole year?
You cannot claim an adult child (assuming this is the case) as a dependent if he or she made $4,050 or more. It doesn't matter how many months she worked or didn't work for this income "test".
See Exemptions for Dependents
Did your daughter also claim herself when she filed?
