Thank you for contacting Ask Extension. The best time to transplant peonies in late fall is once the plant has finished flowering. It's suggested that you transplant them at least a month or six weeks before the ground freezes, ensuring that the roots have enough time to become established before winter. To transplant a plant this size, it requires great care and attention. Make sure that the root system of your peony is completely dug up. If you need to transplant in late fall, prepare the new location by digging up as much of the root system as possible, then transplant into their new location as quickly as possible.

This is to ensure that the plants have time for their roots to become established before winter, and help avoid the plants heaving out of the soil with freeze and thaw cycles, damaging roots and crowns.

But since we are almost into December, I have a few suggestions. Because the time frame is out of what is suggested above, you can either dig it up now, and ask to plant it at the new site. If that does not work, you can ask the homeowners of your current property if you can come back in the spring, and divide the plant, and everyone wins. Or You can do what I did several years ago, it might not be the best solution, but it worked for me. I dug the plant up, now, put it into another pot, then buried the pot and plant in leaves and soil, to insulate the roots. Remember to water until the ground freezes. Then pull the plant up when you move, but do not plant it until the ground thaws in the spring. But you can again bury pot and plant at the new home, or store in an insulated garage until spring. You do not want the plant to get below 40 degrees in the garage. This is not a certain method, but it is an option.

Good luck with the move, the new house, and glad you are taking your daughter!

I have included some references for you!

https://extension.umn.edu/planting-and-growing-guides/dividing-perennials

Peony care: Dividing and Transplanting Peonies | Matthaei Botanical Gardens and Nichols Arboretum (umich.edu)

Peony – Wisconsin Horticulture

Dividing Peonies | W.E. Upjohn Peony Garden (umich.edu)