It's funny, but I think the start we've had has ironically made us more nervous about our prospects this season, than a lesser excellent start would have.
The fact that we're performing so well gives us hope that this might finally be the season, and hope is a double-edged sword. Hope makes us fear plummeting to earth, even as it carries us aloft.
It doesn't make it easier when we have a team like Man City, which looks to have the early claim to be one of the all time greats in English football history, relentlessly plundering the points, even as we accumulate our highest ever 10 game total. It doesn't make it easier when teams like Chelsea and Arsenal, which are supposed to be in transition, are themselves having excellent starts.
At the end of the day, it's a competition contested by 20 teams. As well as we perform, other teams have the opportunity to outperform us. And there's nothing we can do about that.
I (and I think others) started the season with an ambitious but realistic target of 90 points for this season. That would be our best total in a PL-era season by 4 points, and would win the league in about 2/3 top flight English football since it went to a 38 game season.
I think that should still be our minimum target - anything extra would significantly increase our chances of winning the league, anything less will significantly reduce our chances of winning the league.
We're currently on target for about 98 points (rounded down). That's terrific. We should celebrate that and keep it going, game by game. That's really all we can do. The less we worry about our rivals' performance, the better.