>>213040557
I think it's fairly reasonable for a movie to give each character one skill that doesn't need to be further justified just as their reason for being around.

That said the explanation for Luke being a good pilot is that he's a space redneck who owns his own ship for whom piloting a fighter is a job related skill, plus him having the force. He also mentions he was planning on joining the imperial academy (presumably as a pilot) in a new hope and his shuttle can even be seen in a blink-and-you'll-miss-it background shot in A New Hope.

It's the equivalent of a WW2 movie having one character be an experienced mechanic because he got his start working on tractors and planned to join the military to be an engineer, and also has magic powers which boost that.

He then proceeds to go through a bunch of training, shocked by droids, made fun of by a troll doll and his hand cut off before he starts being good at fighting. That's more effort and patience than any modern media go to build a character through adversity.