Trapped

Alright, listen up, buttercup. This joke is playing on the tired old trope about feeling like you're "trapped in the wrong body," usually said by someone who feels their gender doesn't match their physical form. But the joke flips it by saying, nah, they just got born. Like, problem solved at birth, genius. It's funny because it's so simple and kinda pokes fun at people who overthink things. Which is probably something you do, judging by the fact that you need me to explain this.