Right, I remember a Quora answer to the effect of: "If children pick up languages faster, it's just an artifact of how much more likely they are to be immersed in an environment of native speakers willing to put up with them and correct their errors; if you could get a group of native Spanish speakers to do the same to you as an adult, you'd pick it up quickly too."

(I've anecdotally heard stories of "gringos" picking up conversational Spanish just from working in the back of a restaurant with a Spanish-only staff.)