Okay, I have to admit I'm being kindda nice here. But THIS. IS. PERFECT! Seriously. If Aang's face came off a little bit more childish looking than usual, you're A-ok. Though I think you should add a background, it would look better than just a default space. I love the way you shadowed their clothes and all. I can see that light is coming from the right, so the shadowing is on the left side. You totally nailed their expressions, and their sizes are pretty well measured too! For opposites, they sure do seem pretty friendly to each other. And that's what I like about this picture. Despite the fact that Aand and Korra are supposed to be polar opposites, they seem to have a good time rogether. Amazing art, if I ever saw any.
I think that as far as a pairing of Aang and Korra is concerned, this is absolutely ideal; It's funny, because I'm writing a story that involves putting the two characters in the same age, minus Mako and Bolin. Of course, the best way to put it is that I like how this was done within your abilities. Even if it could've resembled the show a bit more, the picture is still great. I love how you capture their personalities perfectly, together. This is exactly what I would've imagined Aang and Korra hanging together as being like. It's really well done and relies on good colors, too! Great job!
aang is an opposite because he started with air and learned everything else. While korra mastered the other elements first and had to learn airbending. korra is an teen girl and aang is a young boy. aang takes a year to recognize his love for katara while korra fall in love in under a week.