could you maybe go into a little more detail on the idea that your aspect can be something that you have to grow into and learn in order to be a better person?

That’s not exactly true however- An Aspect isn’t for you to become a better person, since it would imply that people with affinity to their Aspects can’t be assholes and. I mean. We have many canon examples of this not being the case.

What Aspects can be, however, is something related to Character Growth, say… Let’s take Xefros as an example, because I love this boi. Through the entirety of Act 1, and arguably, for all of his life, he’s thought little of himself, he’s been trapped, repressed, by society, by Dammek not being the best Moirail. And Joey comes along and she encourages him that he can be revolutionary too like Dammek is, that he’s brave and can be strong! And being part of the Revolution, he’s going to be growing into that Rage, learning to have Confidence in himself, and become a powerful force against the Empire. That’s how you grow into an Aspect positively.

You also have, for example, Eridan, who was skeptical of Magic and Faith, but eventually accepted it and had a Wand made for himself. Once he accepted Hope, he became a powerful force that single-handedly knocked Sollux out, and killed two Trolls and the Matriorb in the blink of an eye. Here, Eridan was acting selfishly and being an asshole, but we could see that, once he accepted his Aspect, he became powerful.

The way you grow into your Aspect, or if you already were very tied to it, depends heavily on the individual, and not all the growth has to be positive, but it does expose a visible development.