All I can say is that I'm 36, and my profile is not unlike yours. I worked in business for 12 years, have a liberal arts degree, and my GPA was 3.0 from undergrad and 3.5-ish from post-bacc. I worked as an ER tech part-time before post-bacc, and full-time after. I'm starting PA school in May, having been accepted in November right after the interview at a school with rolling admissions.
My advice is to study for the GRE in a focused and strategic manner. Buy whatever book you like the best as you look at them in Barnes & Noble, and then use all the tools there. Do all the practice sections, take all the practice tests. Space it out over a couple months. If you learn how the test works and know your stuff even just to a pretty decent level, a strong GRE score is likely. And a strong GRE score will be the icing on the cake.
Target your applications well, too. Decide on geography first, then look at how well-established the PA programs are. Is there a 4-year med school as part of the same university? Is there a nursing program? Was the program established prior to the huge explosion of new programs circa 2001 or 2002? Any of the above can be seen as pros or cons. One thing you should look at is the first-time PANCE pass rate for grads of the program. This one is generally felt to be the most reliable indicator of overall program quality.
And one last note as a fellow non-traditional applicant. Even though a disconcerting number of people get accepted to PA school as 22-year-olds fresh out of undergrad, I think the maturity and experience thing is more than just something they say. If you know how things work inside a real live hospital, if you've had some life experience, if you know how to be part of a team and how to be responsible for something, then these things carry some weight. And anyway, a school that would rather take the 22-year-old with a 4.0 from their new Biology degree is not a school you'd want to be part of.
