How big should a 17 month old yellow rat snake be?

[poomwah]

I saw a lot of information on this site, and a few familiar names, so I figured I'd join.
I recently got a yellow rat snake, and I'm wondering how mad I should be at myself. I'm very disappointed with the snake I received, and I'm wondering if I should have expected more, or if I was unrealistic to expect what I did.
I had a choice between a 2012 or a 2013, obviously the 2012 was a lot more money. I chose her because I feel more comfortable handling slightly larger snakes. The snake I got, born either august or september 2012 (the breeder wasn't sure which), is very small. At least a lot smaller than what I expected.
She weighs 29 grams. This seems incredibly small for a 17 month yellow rat snake. Am I correct in thinking this? Or was I unrealistic in my expectations?