Mate(w)vsArnaud(b)

Hi - my sister came to my appartment to wish me a merry christmast with her friend and her boyfriend. I've never seen that guy in my life, and he sees my chess sets and asks me 'are you good at chess ?' I answer, i don't know, trying to get better everyday, what about you ? He pretends he's a deadly attacker and that he could probably beat me - he wants to play.
I accepted without much confidence about myself, he was intimidating -  we decided it to be a 20min game - i've been studying chess for almost 7month now - i told myself i should maybe beat him - the only problem is that i really did not know how good he was

I used Nimzo indian defense, because i am reading a book about it and i'm halfway done - i still have problems finding mates, so i'm glad he resigned.

I've win the game, but i want to know if i've miss some good moves.
Thanks for reviews, much appreciated.