You're off and running is an idiom meaning that you're making a good start, progressing well. Example: As soon as she started in her new job, she was off and running . Originating in horse racing, it is the traditional announcement at the beginning of a race ("They're off and running! ").

I consider the phrase "you're off and running", when spoken to an individual, as a fairly patronizing expression, offensive and condescending, in other words. It is not praise, certainly.

You're off and running means to a lazy person, they are up and doing something, rather than sitting there doing nothing. If told at work, it would mean you understand job and are doing well. Off and running in race horse terms means out of the gate and racing strong. Most times I would think it as a praise to someone.