Hii!! I really like your art, but there are some things that could be corrected to improve your drawing :) The mouth seems to be very low from the nose and very close to the chin, so I raised the lips and the tip of the nose up (That's why it looked weird to you (⁠ ⁠´⁠◡⁠‿⁠ゝ⁠◡⁠`⁠) ) I slightly changed the nostrils, made the neck thinner, smoothed out the shape of the face a bit and added highlights to the eyes! I also thought it would be nice to add more volume to the hair and add a little shadow and light on hair. I hope he looks more like a teenager. I would also recommend crop the drawing a little to get rid of some of the excess space in the background. I hope this helps ^-^