Fast Win

I play this game earlier this day &... well you be the judges. tell me what  could have been done to stop this checkmate... i know against a stronger opponent this won't work.

 thanx, i will be careful from now on.

You should never bring out your queen that early in a game, unless playing an opening (like Scandinavian) where it's safe. 

I know you won, but against better players you will get dominated until you learn to develop minor pieces (knights then bishops) before moving your queen.

>5. ... Bxg5 and black is in a losing position.

That move is  impossible ... White should have played 6. Bg5 , and the queen has to leave that square.

 wow... i really need to pay attention from now on... thanx all of you & keep it up. your opinions are really useful for me. again thanx all of you

6. Nd5 for white. Q has to move and guard c7, then Ng5 attacking f7.  Look at these:

2...Nc6 is a better move than 2...Qf6. Also,  5. 0-0 was better for White, and Black is losing. 6. Bg5 and 6. Nd5 also are good.

My advice: don't try this idea again.