Hello this is my last match, i played as white , do you think it was good or bad , middlegame

The passed pawn is weak as white cannot support it.

Why do you think a3 on move 10 was bad move. What would be better. Nobody like knights too close to my base.

10 a3 was bad indeed: it is a loss of tempo as black wants to trade the knight for your good bishop even without being prompted by 10 a3. 10 a4 was better so as to exploit black overextending on the queen's side.
4 e3 was bad: too passive. With 10 Nb5 you could profit from black's awkward move 3...Nc6.
6 Nge2 was passive: 6 Nf3 is much better as the knight can leap to e5 later. On e2 the knight has no prospects.
7 h3 is passive and weakening you could still play 7 Nb5, as Bf8 is now on g7 and can no longer defend with 7...Bd6.
9 b3 makes no sense. It is a useful move to prepare Bb2, but your bishop is on f4. Better 9 a4 to punish black for his overextension on the queen's side.
Those are all minor mistakes: at your level games are decided by gross blunders.
In this 15+15 time control game you end up with 15 minutes useless left on your clock. You should utilise your time. Around move 30 you should be near zero on your clock so as to finish the game on increment. Taking time to think will allow you to play better.

Thank you for advice , Will apply this new info it to next games