I'd say with the move 5.d3 opening is very passive for white. So, instead of developing your c3 knight try to exchange pawns by playing c3 and then d4.
6.Nh4 - is a blunder since it looses the e4 pawn because after 6...Nxe5 7.Nxe5 Bxh4.
Overall you played good . Good luck on your future games!!!
3. h3. Very passive. 5. d4 is a much better move, at least, Paul Morphy thinks so.
You should develop your pieces instead of going for an attack that's not there. You are lucky your opponent gave up a bishop on f6 for no reason. Otherwise you are behind in material. If your opponent is even a decent defender you won't get a checkmate.
Your bishop hangs from move 12 and forth. other than that... h3 is NOT a good opening move. stick to the principles and develop all your pieces first.
6... Nh4 same here. BLACK is the one ahead of development. BLACK is the one to attack. You should complete your development before attacking (you also violate the principle of only moving a piece once in the opening)
My opponent's rating was 1184 and mine was 1237.
White (me) wins!