If I made a mistake and filed single instead of head of house hold can that delay my tax return?

Probably not. The IRS doesn't predict your accurate filing status. It can change from year to year according to circumstances.  You can amend to claim the HOH status.

why does Turbo Tax insist on my filing single  I can file HOH

How can I do that    File HOH

Go back into the Personal Info section and answer the questions regarding filing status. You have to qualify to be Head of Household, it is not just a choice.

 

Head of Household

You may be able to file as head of household if you meet all the following requirements.

1. You are unmarried or considered unmarried on the last day of the year. See Marital Status , earlier, and Considered Unmarried , later.
2. You paid more than half the cost of keeping up a home for the year.
3. A qualifying person lived with you in the home for more than half the year (except for temporary absences, such as school). However, if the qualifying person is your dependent parent, he or she doesn't have to live with you. See Special rule for parent , later, under Qualifying Person.

Qualifying Person

See Table 4 to see who is a qualifying person. Any person not described in Table 4 isn't a qualifying person