good rating for 3 minute blitz.


Good has no meaning. You can see which percentile your rating puts you in. Your blitz rating of 911 puts you in the 44th percentile. It’s up to you to decide whether you think that’s good or not

If your friends are at 800, then your 900/1000 rating is "good". However, if your friends are 1200, then that same 900/1000 rating becomes "no good".

Also, ratings 400 or more points below a person sort of run together and seem the same. Like skills from near-beginner to 1500 seem about the same to me.
But to a grandmaster I'm like a beginner too. So it just depends.
In reality, if a person is 1500 blitz on chess.com, then they've probably been playing (and studying / learning) for multiple years.
So like others have said, it depends how good your friends are (and maybe also what your goals are). Also like @mitsud implies, if you're under 1000, then you're probably still close to beginner level (probably been playing chess less than a year).