Ramona Mom to 2 great kids and wife to one wonderful hubby since 1990!
I also think that the maturity of the child and the neighborhood that they will be alone in is also a consideration!
Sounds reasonable to me!
One recommendation that I have is that you have your daughter take a babysitting class.
Not to worry, she's had tons of first aid and safety training through Girl Scouts (she's in her second year as a Cadette) so she's pretty savvy there. I think a babysitting class is a great way to get those skills, though--wish they'd offered them back when I was a tween!
Scouting is a great way to get those skills!