Most breeders don't seem to include a certificate of health - unless shipping of course - but they should offer a short health guarantee. Most seem to offer a health guarantee for 2-4 days or so, just long enough for you to get the bird in for a checkup. I'd ask about a health guarantee.
I would also ask about the food she's getting now, especially what if any soft foods or weaning pellets she's getting so you can be ready to offer some if she regresses a little.
Since she's clipped now it's a little late to do anything about it, but you could ask if she was fledged (allowed to learn to fly). A responsible breeder will let babies fledge and learn to fly well before clipping (if they do clip). Clipping a bird before it goes to a new home isn't bad - it can sometimes be safer when a new bird is settling in and doesn't know where things like windows are yet - but birds that are clipped before fledging tend to have more trouble learning to fly later and may be less active or clumsier.
