It was worse than in the movie.
“This is perhaps the most glaring way that 300 sugar-coats the agoge. In the film, Leonidas graduates by slaying a wolf that was hunting him. But it is almost certain that the real Leonidas graduated his Spartan training by stalking and murdering an unarmed, untrained man at night. Some mother’s son, some sister’s brother, some child’s father. Our hero, ladies and gentlemen.”
https://acoup.blog/2019/08/16/collections-this-isnt-sparta-part-i-spartan-school/