Will this “work” retroactively for 60K + entries?

Is this going to freak out if we have 60k+ entries currently in the DB? I set this up to run every 7 days on entries older that 2 months…which will be great for us going forward…but what we really need is for this to clean up what’s already been stored.

1) Will this clean up all of those old entries?
2) Will there be performance issues or any problems because there are so many there now?