I think that depends on the length getAge(). If it's 3 lines, 'p' probably is fine. If it's 200 -- which, perhaps it shouldn't be but that's another issue -- then person is probably a better choice because you may lose the original context as you scan the method.

Also in Java if you use intellij then you'll probably get 'person' as an autocomplete, which actually makes it roughly as easy to type out as 'p', (and a better choice if your entire team has standardized on intellij.)