Not "I wanna be an artist," and not "I'm gonna be an artist." Rather, "I'm [currently, sure as I'm sitting here, no doubt about it] an artist."
One of her friends, a little older than her, was complimenting her on a picture she drew. Intended or not, Alexa perceived it as patronizing. And she wasn't having any of it, at least not from a near peer.
And sure enough, she is an artist. She created these lovely flowers today without any help from mom or dad.