Hi lucyanne,
which dolls house was it? I think i agree with Boo, the fisher price/little people stuff tends to be good. If its one of the old fashioned style ones, not sure if she'd fully appreciate it at 17 months, but if you saw it at a good price you could aways put it up for a later date.
The thing is, all children develop at different stages and ages, and you know Katelin best. Niamh wouldnt have been ready for it at that age, but would be now, as in the last couple of months, she's really been into imaginative play.
Sorry I cant be more helpfull.
let us know what you decide.
Kas xx