She would be 45. I have seen people in profiles recently that had children through their 40s.
Both profiles in that merge have birth year about 1815, but with no sources, it is difficult to determine. The Marriage Notice date is the only thing and it has no ages or parents.
Checking the 3 children on the other profile, it looks like Eleanor was born about 1828. There is an 1861 census on Charles Mowbray, middle child, that has Eleanor, head of house, age 33, Hartmoor, Durham with the three children.
If the PM is sure about the death date, then I would reject the merge stating that she is sure of the death date and stating the 1861 census shows that the wife of Charles was born abt 1828, not 1815