Age and Graduate school
Anecdotal, but: I was 31 when I started my PhD, and it wasn't an obstacle at all. There were more than 80 applicants for two places. I have the impression that what matters a lot (at least in neuroscience, at least at my institute) is how much training the supervisor would have to invest in you. I've seen many times that the applicant who already did some similar research gets the position, even though there might have been someone else who is in principle just as good. Previous research experience carries a lot of weight.

From what you write, it seems to me that you would have a very good chance in getting into a program - publications and good GRE scores are both a big plus. Recommendation letters are also important. I would be surprised if your age would be an obstacle. But beware that it might be an obstacle for some sources of funding! I don't know if it is the case in the US, but I'd guess that's the only potential problem with your age. 

...And now we wait for someone on the other side of the application process to give their answer :)