(conflict of interest - the artist's a friend of mine.)
it's basic but i like the colouring, especially the muted contrast between the eyes and the hair. that adds a slight degree of realism, which i think you wanted. however, i would adjust the white and the skin colour, reducing the contrast between them and the rest of the image until the contrast is consistent. the background's a little too light for my liking, though it might be an in-between between the light colours and the darker ones.
i know that you put a lot of effort into each stroke since i've seen you draw, but give the line tool a go for sketching ideas. i fucking love the line tool! trace over it afterwards if you want. vary the thicknesses of the lines gradually if you want that too.
next time you might want to try a more expressive pose - something that captures what looks like an unsure emotion. i'd also add a few more things to the suit - some markings here. if you want something adventurous, make them look like they just got into a fight with a bear and somehow won but not without some PTSD.