I literally just played (and analysed) this game and had to show off, show it off I mean ;)
I think this is pretty damn good for a 1200 player, especially in 10/0. Any comments and criticism welcome :)
6. e5 could result in blacks response 6 ... Ne4, forcing you to play 7. Nf3, followed by 7 ... Bg4 and you are boned. 6. a3 was a good move. Nice mating net, btw.
I didn't quite think that was right so I ran it through an engine and... Turns out e5 is the best move. And Ne4 just is horrible because after a3 the Knight is gone. No way to save the Queen and the Knight.
You are, of course, correct. Forgot about possible 7. a3.
16.c7+ is mate in two, not 6