I'm probably not the best person to ask since I'm currently suffering angst for starting DS in daycare...Personally I do think 12 months is too young, but then we started DS at 16 months, which is not much older so I'm just a hypocrite!
Needing time out does NOT make you a bad mum. If you're comfortable with the daycare centre and feel good about the staff there then you will know your DS is being well cared for while you get a bit of time out to care for yourself.
Is XH volunteering to give you a day off....?