LeBron recorded his 1000th assist at 20 years old.
Magic was 22 and Stockton was 23 when they recorded their 1000th.
LeBron James NBA & ABA Statistics | Basketball-Reference.com
It looks like LeBron is going to be the youngest ever to get 20,000 points as well at 28 years old. With Kobe reaching 20k when he was 29 years old.