A brief, gentle word of caution...please be certain that the dog comes from a reputable breeder who health tests their stock, shows their dogs, and who will be your mentor. There are lots of threads on this forum that discuss what to look for in a breeder.
The reason I say this is that Newfs are prone to a number of diseases and physical ailments themselves. If you want a dog that will physically help support your daughter, that dog must be in excellent condition herself. Be sure when buying a pup that the breeder does not send the dog home before it's 10 week cardio exam which should be performed by a board certified cardiologist, not the corner vet.
Also, for any dog you are looking at, get her AKC registration # and do a search for that number on the
OFA website. That website has a lot of good information on orthopedic and other health issues, and they maintain a database of dogs that have been tested for breed specific ailments such as cardiac, hips, elbows, cystenuria, and others.
Since you want this dog as a service dog, I think you should set your criteria high. It costs a lot to train service dogs, so you sure don't want to spend a boat load only to have the dog keel over from a heart problem or find out his joints won't allow him to do the job.
Also, get references from the trainer and make doubly sure they have a lot of knowledge about Newfoundlands. This is a breed that does not respond well to certain types of training. And a Newf that has "shut down" won't be of any use as a service dog.
We are here to help if you have questions.