If you mean play AS her, You can't. If you mean AGAINST her, you battle her several times throughout the game
Bianca
Bianca gives it to you
You get it in Narcene city from Bianca
Black, Cheron, and Bianca are 14 in the manga. White's age is yet to be revealed.
Pokemon Black and Pokemon White are the official names.
I believe she goes to Nuvema Town, that's where you can battle her
in your own room,after that you have to battle both bianca and cheren
You of course no, you, bianca (bel), cheren and maybe N
After you finish the game (completely) go to Professor Juniper's lab and Bianca will be there. Talk to her and your ready!
After beating the Nacrene City gym
After you beat the 5th gym Bianca, she will give you the HM02 Fly
Bianca gives it to you in Nacrene City after Team Plasma steals the dragonite skull