yea, if you put new pads on, you either need to get new rotors, or have your old ones turned. Your old pads and rotors eventually get little grooves and inperfections in them. When you put new pads onto your old rotors, those little grooves and inperfections transfers onto your pads and basicly turn into thick shitty copys of your old pads.
Since your doing them all the way around, It would be a good time to completely change your fluid. Do this by just bleeding, and when the fluid starts to come out clear, then your done with that side. It takes a while, but it is worth it.
Also, if this is your first brake job, I garentee your going to have problems with the little screw on the rotors. To remove them intact, your going to need an impact driver. However, the screws are not needed, since the reason why they are on there, is because, when the car is assembled, the wheel is put on basicly during the final stages, but the other parts are put on earlier. To keep the thing aligned, they put the screws one. They are just there for the assembly line. Just use a drill and drill the screws out.