I have to go against the majority here. I too had an obsession with ferrets growing up and i wasn't allowed them.
i now have 2 boys ( pepsi and lemonade) and i have to say they are not hard work. (no more than other pets)
We converted a shed into a large house/ cage for them. They have ledges, tubes, toys an eating area and a sleeping area and they love it. We have reigns and take them on walks. ( also into local schools and nurserys)
My 3 love them, but due to their young ages, we only let them out when both my dp and i are there to make sure of safety.
My ferrets are trained and come when caled, have never bitten, though do have sharp claws when climbing up my back.
Yes ferrets are more of a pongy pet than say a cat, but they can play and curl up and sleep on you like a cat, can take them for walks like a dog and shut them away (when people with allergies or scared come over) like a rabbit.
We (touch wood) havnt had any reason beyond yearly checkup to go to the vets and we love watching them.
We keep an old shirt in the shed and pull that on for their nightly cuddles, poo scooping and water changing etc. So it keeps your clothes etc from smelling, but you get into a routine and it doesnt seem to much trouble.
If you are used to horses etc then ferrets will be easy in comparison. They truely are wonderful and i think you should give your dd a chance.
ps if your anywhere near more she is welcome to come round and play with them etc.