Oh that was quite delightful! In my mind I saw Harry as a bit younger than 10. His mannerisms reminded me more of about 7.
What I truly loved about this fic is the predatory undertones, where you are, in effect, watching someone who has his intentions for the evening mapped out completely, and then you watch as Harry walks into each and every one of Severus' traps. I wonder what the moment will be when the trap springs shut and Harry knows he is fucked. ... figuratively, of course....
For a first attempt, I think you did brilliantly, and I hope to see much MUCH more work from you!