When do brake rotors need replacing? 2015 SQ5 specs
 

Hi All,
I recently took my 2015 SQ5 (40,000km = 24,900miles) for servicing at a "reputable" Audi dealership. Got a call from the Service Advisor recommending to change to my brake rotors. He said the brake pads were still good.
He provided the specs and I suspect because I am a female, he was giving me the safety recommendations to get them changed before the sensor light goes on. Also, don't brake pads generally need replacing before rotors?

My car brake rotor specs:

Front:
Left - 34.60mm
Right - 34.47 mm

Rear:
Left - 21.01mm
Right - 21.16mm

Researching google, I found the following information. I think I should be ok for another 6-12 months or so??? I only do city driving and don't drive it hard. Any thoughts/advice?

SQ5 Front:
brake rotor new 36 mm
brake rotor wear limit 34 mm

Rear:
internal thickness 22mm
brake rotor wear limit 20 mm

Thanks in advance!