
Why does she want to go on a waiting list now?
3 years is a long time to sit on a waiting list and she could spend some of it in looking around and really pay attention on where she wants the dog from.
She might see the perfect bitch with the perfect pedigree and decide she wants a puppy out of that bitch, that bitch might have not even been born yet :).
She might see a dog she wants a puppy from so will then need to find out who is planning to use that dog and whether she likes the bitch too.
If she already knows she wants a dog from certain breeder I see no harm in getting in touch and getting to know the breeder.