hang in there, time will tell! I have a black poodle with blue skin. She's 4 and she's black as black, but throws some blues in her litters. Seems like (from my limited experience) that you'd see some gray cropping up somewhere by now if Belle was going to go to blue.
By the way, "Blue" is what many Doodle people call "silver" - or the classic lighter graying/bluing on the fronts of the legs, and muzzle. And in another post I said that it is a close 2nd place in my favorite colors.