Rising times are variable, they depend mostly on temperature, the times given are approximate, but you'll be able to see if the dough has doubled, if not just give it more time, I promise it will rise! A good test to determine if it's time to punch down after the first rise is to insert two fingers in the dough up to the second knuckle, if the holes remain, it's ready, if the dough springs back, give it more time.