I'm a novice player, trying to improve. In the following game I played as white recently on chess.com, I analysed afterwards and my worst move of the game was apparently when I castled. The engine strongly favoured trading queens on move 9.
[FEN ""] 1. e4 e5 2. Nf3 d6 3. Nc3 Nf6 4. d4 Nc6 5. Bb5 Be7 6. Bxc6+ bxc6 7. dxe5 dxe5 8. Nxe5 O-O 9. O-O Bg4 10. Nxg4 Nxg4 11. Qxg4 Bb4 12. a3 Bxc3 13. bxc3 Rb8 14. Be3 a5 15. Bd4 Rb4 16. Qxg7# 1-0
Why is this? I can't quite see why the trade is beneficial, and so much better than castling at this point.
Maybe I'm giving up initiative by allowing black to initiate a trade? Or perhaps I'm better developed, so it makes more sense to trade down and benefit for more activity with my pieces? It was a strong 2 point difference from what seems like a fairly even choice from my perspective.
Any ideas why the castling move at that point was such a bad choice?