Wookiepedia says he was probably born a year or so after the battle of Endor; if true, the guy's pushing thirty in Episode 7. By the time grandpa was thirty, it was eight years after
Revenge of the Sith, and was pretty much the stone-cold badass Darth Vader we saw in the original trilogy.
It really is interesting the direction they went with Kylo Ren. He's got the whiny gene his grandfather and uncle Luke had, and obviously has an unhealthy amount of "villain worship" of him, but he's got the formula completely ass backwards compared to Anakin:
Anakin Skywalker did evil things to gain power; he wanted power to save the people he loved.
Ben Solo kills the people he loves to become more evil; he sees becoming more evil as the key to more power.