I really like this sonata. You've got a good tempo, I think, but it sounds a bit like you're in a hurry to get through it. It's a good humored, witty piece, and you should maybe enjoy it a bit more as you play it. Very, very brief pauses for breath between phrases would give it a more relaxed, good-natured feel. And as you said yourself, a bit more dynamic contrast would be good; terraced dynamics.
Your left hand ornaments in the development were very good and crisp.
This movement reminds me of the last movement of the Mendelssohn violin concerto.
Good luck on the exam.