Hey,
Ive been changing brakes ever sense I was a kid. Its a very easy process and it does sound a lot like your mechanic is just trying to get an extra couple bucks. the toughest part of the whole process would be to bleed your brakes and to say it best. if you did change an a/c compressor in your car, brakes should be a breeze. just make sure you have a break bleeding kit(you can get these at pep boys for 15 bucks.) also make sure you take your time and dont try to rush.. this is your stopping power haha. lemme know if you need any help with the process and ill explain the best I can.
Chris