Missed amazing Mate!

Hello everybody. Above is a game I played against a much higher-rated opponent. In it I missed a very impressive checkmate, but nonetheless played very solidly, I think. However my limited Chess knowledge (having been playing for exactly one year only), restricts me from understanding the deeper intricacies of the game. There may be elements I have missed. I understand that in order to better myself, I should analyse the games I have lost; yet I am far too proud of this victory to neglect it; and I feel like showing everybody it. 
    I have annotated the game where necessary. All types of feedback are welcome and very appreciated. Thank you.

For those of you who just want to see the missed mate opportunity - it's from move 22.