whats rating

It means they are very good players.  The actual numbers run from 0 to 2900 these days. The numbers don't mean anything but show position relative to other players. In general, the higher your rating relative to your opponent, the better your expected results.

Beginners can start out here with an 800 or 1200 rating. As you play games, your rating will adjust to a more or less stable range. Don't be discouraged if yours goes down for a while before it stabilizes.

Your rapid chess rating is 1053 after 11 games.  It is not yet clear where your rating will stabilize. You can look at the advanced stats and see that your rating is better than about 39% of recently active rapid players.