No, Cody... If you are a true 13 on a measuring device, get a 13, not larger. In snowboarding, you definitely do not want big boots, if anything most people get them on the small side. (less toe/heel drag) Also, if your foot moves around, you will either fatigue your body from your foot always cramping up from trying to grapple the bottom of the boot. Or, you'll be swishing around so much that your toe will jam forward to the front of the boot on toe side turns giving you some gnarly bruises. My advice, true 13 rocks a true 13 (or a 12.5 if you want to rock foot bondage a bit :) After a while the boots will pack out a quarter of a size.

I would try as hard as possible to try the size on before you buy it. A lot of times people will make the mistake of buying shoes online that don't fit properly. The fact is, you should buy a size 13 or even a 12.5 since after a few days of shredding the boot liner will pack out about a half size.