I appreciate what you are saying but you need to let go bit. If you don't let them grow up themselves they will become socially inept. All the mummy's boys get bullied and you really don't want that! It's not a good thing to happen and it must be a terrible thing to balance.
EDIT: I'm talking about the park and similar stuff! 7.30 is just about right for an 11 year old - she's not old enough to look after herself.
I agree that i need to chill about it, i've just yet to find a solution for doing so. Have suffered with my nerves since my teens, it's not a nice thing, not for me and definately not for the kids. However, they are generally happy and content.