Silica isn’t really much of a fighter. She has a pet dragon which can help her in a pinch and just by playing the game for so long I’m sure she is at a reasonable level. That being said, Kirito was a beta test player of Sword Art Online and has been intensely leveling up for quite a while. I don’t think Silica would be able to catch him at this point even if she spent years training. Kirito was just made to be a sword fighter and his skills are at the human peak. Silica would get speed blitzed as soon as the round started. Kirito wins.