I think 11.5K is very quick wear for city driving

Certainly possible

if you do work yourself take out the pads measure thickness - compare to minimum thickness for usage from MB specs for your car - and for under five dollars install new pad wear sensors if brake pad and disc thickness are within spec. Then see if the light turns off

Might as well use a lttle brake cleaner and stiff brush and clean up things.

And your sure it is brake wear indicator not brake low fluid indicator, just asking