Hello. I'm glad you've turned to AaEx.
Our peony expert took a look at this and determined it is . . .
called 'Do Tell', hybridized by Auten and introduced in 1946. The exact form of the flower (the peony is classified as a "Japanese" variety, where the stamens have evolved into narrow petals called stamenoides) varies a bit. Also the color of the guard petals vary from pink at the opening to white after a few days. If the weather is hot, the petals will whiten almost immediately.
She shares this photo of one just after opening in her garden (attached).
I hope this information helps.