S.F.
It's all about quality, not quantity. If the time you spend with your baby is focused and she is the center of your universe at the time, it's quality time, whether it's 15 minutes or 15 hours. If you're spending 15 hours with your baby but not really focused on her (doing other things) then maybe it's less quality.
Having said that, don't feel like EVERY minute must be quality time. You still have a life to lead and a household to run. But, as long as your daughter knows you love her and will be there when she needs you, you're golden.
I've taught 7-12 grades for 20 years now. I've had students who were awful come from both SAHM families and working parent families. I've had an equal number of great students come from SAHM families and working families. No one "family type" makes better students.
Bottom line...happy moms make happy babies. If you're home and you're miserable, you're not doing your daughter any good. If you're at work and your miserable, again, you're not doing your daughter any favors. When you're away, enjoy being away. When you're home, enjoy being at home. Guilt doesn't do anybody any good at all.
Good luck!