you should not handle him for a couple days to around week and then try feeding again.

if youre going to get a 15 gal tank youll probably have to spend more money later on to upgrade to a bigger size tank when the snake grows. if you havent bought a tank yet it would be a good idea to stick with rubbermaids and go with a bigger size(for reasons mentioned by azureN1ght). rubbermaids hold humidity a lot better and humidity is a very important factor to your snakes health. it is very possible to keep humidity up in a glass aquarium but it is going to take a little more work.
just a suggestion.