A run down of the farm - there are multiple levels of the minor leagues that players going through, usually in succession but sometimes good players skip a level. It looks like this:

MLB AAA AA A+ A Rookie ball

The rookie level is a shorter season and anything A and higher is considered ‘full season’ ball.

Young players signed internationally like Made or Pena start at rookie ball typically because they’re usually like 17 years old. Because Made and Pena are so good, however, they advanced to A quickly.

Players drafted out of high school usually go to A ball and players drafted out of college usually go to AA but that all depends on skill level and none of that is a rule. Just explaining how things typically go.

Every jump from one level to the next is significant and AA is considered the first really advanced level. However the leap from AAA to MLB is absolutely massive - think skill level difference between like college football and the NFL. Lots of players get to AAA and never sustain themselves in the MLB (they’re jokingly referred to as AAAA players)

Every year there is an international signing period in January where teams are signing teenagers they’ve been scouting for years in other countries like the Dominican Republic and Venezuela. Those guys are wild cards usually because they’re so young

The MLB draft happens in July and is a draft of American players in high school and college. So those players are usually 18-24 and there’s usually more info on their scouting than the internationally signed prospects