The other (pro) side of the argument is always, 1) shelf life of a baseball player being short and 2) assuming you want to play pro ball, when is the best time to start learning how to be a professional baseball player, next week, or a year from next week?
Which team drafts you also plays a big role. Ideally you get drafted by a team with a shallow talent pool at your position and nothing but aging back ups at the MLB level.
That was Lucroy's situation with the Brewers. He got the break he needed early and ran with it. There was a guy in front of him in the Brewer system, who told the team he didn't want to catch anymore. That guy was out of baseball in a year. Then when he got called up, he replaced some guy named Greg Zaun who was about 35 when he got hurt after about 10 games.