for the record, it may be normal, just that you're not used to dirt bike brakes.
I just added fluid, and replaced the rear brake pads on my yz125, who's pads were down to the metal. NO idea on the condition of the brakes, but didn't have the time to bleed or rebuild the master. I rode homaston dam on sunday, and thought to myself "man these rear brakes suck why do they suck?!" however, after meeting up with some friends and trading bikes, he was complimenting my 125 pads to his ttr230 drum brakes. I think you're expecting too much out of your rear brake, they do kind of need to be mashed to provide stopping power, the point is to mash the rear and tap the front if you need to stop short. Even before I trusted my rear brakes I had surprisingly good stopping ability around a blind curve
at 65-70 mph, in the rain, on pavement, when I mashed my rear brake.