agquad
I would recommend Aerocity as this is you and your daughter's first visit to Madrid.
A great way of seeing where you are going and getting your bearings.
Using the metro is fine for future visits (and so ridiculously cheap), but you cant tell where you are going because you are underground. OK - you can see on a map where you're going, but you can't SEE where you're going.
On my first visit to Madrid, I used Aerocity and did have to share it with two other passengers which added another 10/15 minutes onto the journey, but I just looked upon this as extra getting to know the city time in comfort
Jo