OP, do you live in UK? The reason I ask this is that I don't and what you describe is a bit how our dogs live. They do live outside mostly (sleep inside during 3 months of winter only). We have larger properties generally so there is a lot more space, to put big kennels, have shaded areas etc.
They do spend time in the garden when we are not home, but there again it is a little different as there is usually always someone at home, if it isn't me (I work from home), then my helper is here. Even though I am at home, they are usually outdoors anyway. This is by choice I should add, our Lab will come indoors sometimes (if its extremely hot he will lie on tiles). We have fully enclosed gardens, so they cant get out, and someone else cant take them either.
So, I think that a lot of things depends on the circumstances that you live in. If you don't have the space then you really shouldn't consider a big dog. You also need the time to train them from puppy (believe me this isn't easy having a pup myself).
I have a 12 year old dd too, so I know what they are like with their fluttering eyelashes You do know that it is you who is going to end up feeding puppy mostly, visiting the vet, bathing the dog, walking etc. You cant let all of that lie on the shoulders of a 12 year old....
I know someone mentioned it, but what about a cat? They are much more independent and are mostly lovable animals.
You did say that you weren't all that keen on a dog, but they will be part of your family from day one for at least 12 years onwards, so it is going to alter your life as it is now.