A draw I should have won

This the first topic I post on this forum. I should have won this game, but it ended with a draw by repetition :(

 Please give me advises even if they don't seem to be important.

Thank you !

boring game, but y didn't u move ur queen diagonally 1 on move 7? 

17 Na6.  D7 would have been a better square for the knight.  Knights need to control as many squares as possible and placing it out on a6 does not accomplish that.

23 Nxa2, wrong time to be claiming pawns.  Not only that, but you needed that knight in the center to aid your king.  D5 would have been better.

I agree with xilbus on both points.  Had you played 17...Nd7, you could easily have played 18...N7f6, with strong central control and an extra piece.  In the game, you still could have played an effective 18...Nf6.

23...Nxa2? was horrible.  You already have a clear material advantage.  There are much more important things to consider.  I prefer 23...Qg5, making room to activate your useless rook on a8, putting some pressure on the king, forcing White to consider future problems on the back rank.  If you had made any effort at threatening your opponent, in just about any way, this game would have been a walk.

Long story short, spend less time trying to fork everything your opponent has and more time considering his threats, what your real advantages are, and how to keep the initiative. 

9...Bg4 10 f3 Bxc1 is strong. 

I think 10 ...exd3 is very strong compared to 10...Re8 (which is overly cautious).

 In general, once you have an advantage, avoid playing timidly.

"Because if I don't play this move.
_24. Qc6 ...Kc7 25. Qa5 and I lose my knight."

Yes, but the knight doesn't matter. 25...f5 and you win the bishop. Plus ...Kc7 is a much safer square for the king. 

Oh, yes ! Thank you for all your comments. I knew I had done quite many mistakes in this game but I didn't find them.