Any astronomers or statisticians that can chime in here so I can know what my level of concern should be? Let's say on a scale from 'whatevs' to 'drop all hobbies so I can prep'.
See also
They're newly discovered, but they've been avoiding Earth for billions of years, and will continue to do so.
There have even been suggestions to send an asteroid searching telescope satellite to some lower orbit around the sun and use that vantage point to look outward towards earth and find anything there. Personally I still think we should do that too.
They were always there, and the trends of the last N million years will continue.
Then again, even with a warning, there is very little we can do, aside from evacuate the target area.