My youngest was five when we brought Ruby home at four months old and they get along pretty good. Aiden knows to leave her alone when she's sleeping and he knows how to play with her when she's up, so that works out. BUT Ruby does not like little girls. I figure it's because I have two boys and the only "girls" she has been around are adults.
Anyway, I'm not having more kids so I figure she doesn't have to like little girls
I know this doesn't really help the OP, but I spoil my dogs so much that my opinion is they don't have to like anyone they don't want to. Good thing is Riley loves everybody, so there's one dog kids can come pet.