Can meditation "reverse-age" one's brain up to 25 years?
I have no background in neuroscience but will try to unpack the claim a little bit.
We... found [that long-term practitioners of meditation] had more gray matter in the frontal cortex, which is associated with working memory and executive decision making. It’s well-documented that our cortex shrinks as we get older – it’s harder to figure things out and remember things. But in this one region of the prefrontal cortex, 50-year-old meditators had the same amount of gray matter as 25-year-olds.
In that quote she is specifically discussing a published study of which she is the lead author, "Meditation Experience is Associated with Increased Cortical Thickness". I don't have the technical background to evaluate the methodology of this study, nor to even say whether it actually supports that specific comparison of 25- and 50-year-olds (I see no direct mention of this in the study). But if the claim has any basis in actual science, this is where you will find it. There are other studies that claim to show physiological brain differences related to meditation, but I'm not finding any explicit "brian age" comparisons in the scientific literature itself.
The Inc. article included in the question clearly goes way out on a limb where it states:
Since Steve Jobs was a regular meditator, when he died at 56 of pancreatic cancer, his brain would have been as healthy, active, and creative as when he was much younger.
In this form, the claim is completely exaggerated and unsupported. There is no indication that Steven Jobs own cognitive function or brain physiology was studied directly. The research cited does not support this extrapolation.