Was this Knight Sacrifice a Mistake?

About a month ago, I played in my first tournament in the unrated section. We were not required to record the game, but I recorded the last one. At that point, my score was 2-2, and my opponent was 3.5-1.5. Quite a big difference. I played as black. Here is the game.

I played an attack on the kingside involving a knight sacrifice. When I analyzed the game using chess engines, they rated that move as a blunder. 

1. Was that move a blunder, mistake, or a mistake that turned out well?
2. Looking at the game, and my annotations, are there any patterns or themes you see where I can improve?

Any thoughts?

"Was that move a blunder, mistake, or a mistake that turned out well?"

You had no advantage on the kingside, so the sac was a blunder.

It’s a very bad move. I would rate it more in the category of a total misjudgement than a blunder since it wasn’t an oversight.

If you really want to sac a knight, 4...Nxe4 lol (ok granted, it’s a pseudo-sac).

Hi, considering you rating I would give you some advises, to help your improvement:

1. Avoid do a sacrifices, concentrate in do the basic very well. Let this kind of move when you have a good tactical skills. These moves deserve much calculation, and it is very often see wrong sacrifices made by high rated players. The good sacrifices normally born from pattern recognition of positions, and present a clear compensation in few moves. Let the sacrifices when you are loosing a game and need force a draw, or try an ultimate attack, that is the good moment to do sacrifices;

2. In the game, you did a long castle when you could do a short castle. It is not a bad decision, but you have put a game into a sharp position where you did not how to manage it with precision. In the same way of last comment, you are trying to show the big fish while fighting to put the worm on the hook. In this kind of position is better do a storm pawn attack as soon as possible. One more time, concentrate in do the basics very well before do the next step;

3. So the move 10.(...) - Nxf2 you had an objective, "bring the king out onto the diagonal". But it was not enough to continue with a fast attack. It would very important do a fast attack because after the sacrifice you are in material disadvantage, and play passive here is not more an option to you. You have spent some moves to prepare the continuation of attack, and it was a bad decision.

Good studies and continue playing.

I am with Finegold anybody who plays 3. ... Nf6 is a nut and anybody who replies 4. Ng5 is a nut.
Bear in mind some folks do like to play The Two Knights though.
Now could I resist 5. Ng5 d5 6. exd Na5 7. Bb5+ c6 8. dxc bxc 9. Qf3 hmmm.
6. b3, not me 6. BxB fxB 7. d4 exd 8. Nxd Qd7 9. NxN QxN 10. Qe2 intending e5
I think 9. Nd5 and see if black replies with a lemon.

9. ... Ng4 means I would play 10. Nd5

12. b4, what is that. Surely white plays Kg1, ponders Bc1 or Nd5

14. g3 seems better

15. g3 Qxh3 16. Rh1 Qg4 17. QxQ BxQ 18. Ne3
and black has no passed pawns. White can then chop wood and start to win pawns.

@LeftD "When is it kosher to sacrifice (and knowingly blunder) expecting that your opponent will blunder in response?" My opponent and I are both amateurs, so what can you expect? As displayed later in the game, blunders can be expected.

Got it. And agree. I'm not very good at chess and play for fun. And sometimes I'll take a stupid chance that will fail -- or prompt my opponent into a blunder of his/her own. A fun game is more important than a win, sometimes.

Yes, the knight sac was a blunder.   Your entire plan was inaccurate, in fact.  If you were convinced that attacking her king was the best plan, then you should have gotten your kingside pawns involved too (and also your rooks), instead of attacking her king with just a knight and queen.   Stockfish suggests g4 as a good pawn sac there.   After Nxg4, you would have had a semi-open file for your rooks.  You're lucky that your opponent was a weak player.   You still should have won in spite of the bad sac, since she handed you her queen.   

That was my first impression too, but Stockfish suggests g4 as the best move there, sacking a pawn to open up the g file.   I wouldn't have played that move though.   I probably would have played something like your suggested d5 move.  

I just noticed this idea while looking at your game.  9. Bg4, followed by Nd4, to break open her kingside pawn shield by capturing the knight on f3.   That probably works as well as a sac, but without sacrificing any material.   A kingside pawn storm, before you started advancing your pieces, might also have worked.   Contrary to what IM Bacon said, I think that attacking on the kingside was the best plan (based on the board position at move 9).   You had both bishops, a knight and your queen, as well as pawns and potentially your rooks ready to jump into action.   Learn to be patient and use them all in conjunction though.  Don't just take pot shots at your opponent with one or two pieces at a time.

I realise that. The lines white could have played should have been in your mind and not play the moves you did. I highlighted *critical* points, so look at your move *before* those variations.

Midway through the game, I realized getting my rooks into play just in case I blundered a piece (not shown in the game) with 16...h5. Like you said though, the plan would've worked with a kingside pawn rush, and in conjunction with my pieces. My other problem was when she forked me with 19. Nd5. If she would've pushed the pawn up or moved the king after 13.Bh4+, I would've been in dark waters. 2.

Me too same

It was a mistake bro

That knight sacrifice was BIG BLUNDER bcc black dont have any attack on kingside so that mean that pawn on f2 that black take did not make any problem for him.