Don't sweat it if you aren't sure you want the job. You told them you'd have to think about it--so are they waiting to hear from you, or do you expect them to make contact?
Personally I think 3 evening hours per week (not per day I hope!) is not that bad and your teenage daughter can be responsible for herself during that time. If she were younger I would expect your H to agree that he could be with her for that time.
I think you should make up your mind whether you want it or not. Then call them and either let them know you can't take the job (use the hours as the excuse) or say you do want the job, that you were concerned about the hours, and that has been taken care of. Do it today or Monday at the latest. They will appreciate the call either way, even if they have already moved on to the next candidate.
