Lumb under our Rabbit's teet.

Our female bunny has a lump under her one teet. It's about the size of a grape. It doesn't seem to hurt her when we touched it to see what it was. Is it something we should take her to the vet to have checked out or is it her just getting old?

See the vet immediately.
   
This could be a mammary tumor, particularly if your female is unspayed and never had a litter. If it is caught in early stages it is treatable so do not delay.
   
If your female is unspayed, spay her, even if this issue is not a mammary tumor.
   
As she ages she becomes a ticking uterine cancer time bomb and spaying will improve her overall health and longevity.

Thank you, calling the vet tomorrow.