I think it really depends on how mature your dd is and how comfortable you are. When I was that age I started staying home rather than need to go to a sitters during the school day. My parents woke me before they went to work, called to make sure I was headed out the door on time, I walked to and from school with friends and frequently ate lunch at my friend's house since her place was closer to the school than mine. After school I was not home alone very long before mom and dad were off work, but our next door neighbour was a SAHM, as well as a few other women in the neighbourhood, so there were many eyes on me to make sure I didn't get into any trouble (as a teen I called them "Mom's Many Spies",
). By 12 I was doing short babysitting stints for my brothers and neighbours..by 13 I was the main sitter on our block.
That said, when my niece was that age there was no way she was responsible to be left alone, and she would freak out if it was suggested. She is coming up to 16 and while she is ok if my mil (she lives with my mil in a small town, her mom is here in the city...don't get me started on this situation) goes for the day, Grandma can even take the 2 hour drive and spend the day in the city, but if it's approaching evening my niece will not stay home by herself. She is planning to get her own place here in the city when she comes to college....I do not think she is going to be able to handle it.
My brothers, while responsible on their own, at 10-14 could not be left home together. Too much arguing over who was "in charge"
. Now at 15 and 17, they're fine.
But I think the big issue here for you is that you are not comfortable with leaving her home alone, and I totally understand that. If your gut is telling you to wait, then you should wait a bit longer.