It could be a few things.

#1, if the weed is really dry, it will burn faster

#2, your rolling skills need some work. Roll it tighter, and if the weed is really dry, you have to roll it MUCH tighter.

Dry weed will burn really fast, in combo. with a loose roll job, yeah, it'll burn up in less than 30 seconds.

My joints usually burn a good 10-15min.