She appears to be a mature Narragansett hen. You really can't tell a hen turkeys age just by looking at her once she is mature. My guess is she is at least 2 years old and possibly older. Given proper care heritage turkeys can live well over 10 years. In my experience their egg laying starts...
The link you posted has a picture of a Royal Palm Tom beside a picture of a Calico hen. There is no photo of a Royal Palm hen in that link. Porter's is a trusted source. There are lots of photos of misidentified turkeys on the web. Porter's site is accurate. If the photo you were looking at...
That is definitely not a Royal Palm. She could be a number of different varieties but not a Royal Palm.
Check here to see what a Royal Palm looks like.
http://www.porterturkeys.com/royalpalm.htm