the front brakes do more work.
most cars have their engine at the front. this imbalance of weight towards the front in addition to the shift in center of gravity under braking means that the front wheels have more traction. this means that the front brakes can be stronger without locking up the wheels.

the reason why the rear brakes wear out faster is that typically, the front brake disks are ventilated where the rear disks are not. this lack of temperature management means that they often wear down first.

if you look at car manufacturer websites and look at the specs for the brakes you'll see that the front brakes are usually larger disks with more pistons in the callipers. in some cases they even have much better ventilation (Mercedes not only has ventilated but also cross drilled front disks where the rears are not)

Sure if your the legal guardian and she is underage. I believe you need the same thing at the DMV. Proof of insurance, vehicle registration, 2014 assesment. If really unsure it never hurts to call and find out before you go and you end up not having correct paper work! =)