Same goes for the "wanting to keep it as a surprise" (...for whom?).
If something is supposed to be an important part of the image, it doesn't speak well if you can just later add it without it actually destroying the image/composition. Like the wings. You literally just added them there which kinda shows that they mean little to the image. The dragon would just have been an earthbound creature but not having wings wouldn't have ruined the image, as opposed to say, if the dragon was actually flying or if the boy was interacting with the wings somehow (like if you have an image with a plane in a hangar and a kid is sitting on the plane's wing, you can't remove the wing he's sitting on without it making the picture make no sense).
But now all the things are just props that don't interact. You could remove the boy and it wouldn't affect much, you could remove the dragon and aside the kid's hand, it wouldn't otherwise affect the kid much (he could be resting his arm against almost anything), you can remove the wings and that wouldn't affect the dragon or kid much and so on.
You say the dragon would be a loyal and trained friend (and I assume at least moderately intelligent too) but neither character is even looking at each other or showing any affection (like a rider might hug his horse or a kid his dog or show that they have personality, like the dragon could be licking/poking the kid to ruin the "photo" or the kid could be climbing around the dragon and so on). Both look pretty depressed and uninterested to be there.
And the kid still isn't anywhere near the correct perspective or position. Look at the kid's other shoe which is in profile, and look at the distance between the dragon's wrist and the ring on it's side. Draw your horizon and map out the perspective for the dragon and fit the kid there too.
I still like the dragon's face, but I also really would wish you had planned this image properly and explored more ideas.