"We do these things not because they are easy, but because we thought they were going to be easy" is a surprisingly profound quote. When I ask people who've pulled off remarkable things, it's interesting how many confirm that they wouldn't have started if they'd know how long and difficult the road would be.
One of the biggest reasons it gets harder to do new things as you get older is that new things are generally undignified at first (indeed, this is an excellent heuristic for discovering them) and the older you get, the more dignified you're expected to be.