If you are filing as "married filing jointly", your child must have a social security number and live with you (or the other parent, or both) for more than half the year. Dependents must be US citizens, resident aliens (green card holders) or resident aliens (lived in the US more than half the year).
Since your child is a citizen, she can be claimed as a dependent even if you lived outside the US the entire year, and that question shouldn't even be asked. I am aware of a different bug in the dependent interview, maybe this is another. Or, maybe you did not enter a valid SSN, and that triggered that question.
Answering "12 months" should solve the short term problem, as in fact it doesn't matter. I am more concerned that you should not see that question at all. Does your child have an SSN? If not, delete the child and don't add the child until you have an SSN, and don't file your tax return until the child has an SSN. If your child does have an SSN, make sure it was entered correctly.
