It takes a pile of discipline, sometimes a runner will prepare for a year.
I started running at 21 and I started because I couldn't quite keep up to a cousin while sheep hunting. It didn't happen the following year, I was in top shape
I am 61 now and still keep very fit and it would be impossible to hunt sheep if I wasn't. I don't run marathons but stay in year around shape.
I admire anyone who can run a 3 hour marathon.
I believe it still qualifies for Boston.