It doesn't feel that straightforward to me...
The first time you do this, it seems ok: you ready at some point during time stop, this should mean as usual that you can act _just_ before the triggering action (e.g. an opponent moving).
But then usually the ready rules are such that the triggering action is completed after the readied action (unless the triggering character dies or something similar).
Maybe it's technically correct, but doesn't feel completely fair to me that the triggering action can never be completed (until the last round) because the sorcerer keeps readying a new time stop every time.