administrator account with parental control?
Just create an admin account for yourself, where you know the password, and create a standard account for your daughter. 

If she wants to install something or do something 'admin-y' that you approve of, she can ask you and then you can go and type in your password to change it (Mac's can do this without needing to have the admin account logged in, it will bring up a dialogue box where you type the admin name and password so it's easy for you), however you can also set parental controls to block only somethings, so you can enable app installing etc., for your child, while still blocking sites.