Yep, and Nenneke isn't a mage, so she certainly can't be older than 90 (considering she is still agile).
I've always kind of wondered if she was a mage based off two events in The Last Wish: First during the conversation Geralt is having with her about Yennifer visiting the temple before he did to find a 'cure.' This goes on to be about curing her infertility, which Nenneke says is impossible. Geralt remarks something about there being exceptions to the rule, and from Nenneke's reaction I'm pretty sure he meant her.
Fast forward to Iola's fun seizure when she makes physical contact with Geralt as he's leaving. Nobody is able to do anything to help her until at the peak of the panic Nenneke "Face red with effort" shouts
something which immediately causes Iola to stop moving. Whether or not this was some catechism or chant that could produce results like that is beyond me, but at the same time
Geralt's medallion goes haywire so clearly something magical was happening.
Between these two incidents, along with the fact she's a priestess of the 'god of fertility (and other things)' I really want to say she's got some sort of magic going on for her.
Addendum: I realize my post is really off-track with the actual thread, making a separate one sorry about tha t;p