IMO if you're just starting and want to play Yukiko, I would actually play Labrys first to learn the game. Yukiko as a zoner is arguably a bit harder to play and trying to learn her along with learning the game is going to be that much harder. People are going to be rushing you down and with low health, you're going to be dying before you get a chance to learn much.
To all new players that tell me they want to play Yukiko or Liz I always recommend they learn the game with another character first.