What a precious little girl!!! She's still a baby and will loose her current teeth. One she gets her "adult" teeth, you can brush a couple of times a week. Most times if you provide her with some solid chewing bones (Durabones, or Antlers) those help keep the teeth very clean I do both, brush & antlers.... but I'm also OCD, hee hee :D Just be sure that whatever you give her toy or bone wise that you supervise. Bulldogs are big into swallowing things, which lead to obstructions!
OH my goodness, so precious!!!! LOVE! Start right away to get her used to it. You don't have to use a brush yet, just a cloth for baby teeth, but it will help her tolerate it more when her adult teeth come in. LOVE her!
Any rubber toy will keep teeth white. Yes as mentioned needs solid or antlers but to keep them pearly white its rubber. I give even at the age yours is, marrow bones. The little round cut ones (3-4" x2"thick). All my dogs never had teeth issues. Never...give rawhide!!!! Never never!