Many people employ their children or wife/husband in their work.  You have to make sure it is reasonable pay for reasonable work.  Would you have to hire someone else to do the work your daughter is doing?  And get her a time sheet to fill out like a normal employee.  In Iowa she would not be subject to unemployment ins but not sure your state.  When she turns 18 you have to start withholding FICA. 

Only drawback maybe benefits.  If you provide an employee/daughter with health insurance are you providing or offering all other employees health insurance?