Amy & Rory Aging Curiosities

So in The Power of Three, Amy says she thinks Rory and her have been traveling with the Doctor for ten years from their point of view. In A Town Called Mercy, she (or maybe it was Rory, I don't remember) commented about their friends noticing how fast their aging. That makes it sound like it's been much less than 10 years for the rest of Earth. In yesterday's episode, it's apparently 2012 (when it's not 1938). Assuming that's Amy and Rory's present, that means they've only been traveling with the Doctor for two years, but from a wibbly-wobbly perspective, it's been ten years. So Amy is 23/31 years old.

Rory mentions in Dinosaurs on a Spaceship that he's 31, seeing as he's talking to his dad, that's the age his dad thinks he is. So if that was in 2012 also, that means Rory was born in 1981 and is a good eight years older than Amy. That would make sense, seeing as in The Eleventh Hour, she was 19 and he had already finished nursing school and was working in a hospital. It doesn't work in the flashbacks in Let's Kill Hitler when Amy, Rory, and Mels are all little kids. Rory is obviously around the same Amy in the flashbacks. So how did he land a job at a hospital when he isn't even old enough to have finished college? Especially since he's been working there for 18 YEARS!

And then, AND THEN, <spoilers>in The Angels Take Manhattan, their gravestone says Amy was 87 when she died, and Rory was 82.</spoilers> So Amy is now somehow 5 years older than Rory. Huh? All evidence seems to suggest Rory is older than her. Unless <spoilers>the Angel zapped Amy back to an earlier point than Rory.</spoilers>

TL;DR Amy & Rory's ages =