You’ll Want to Be Over Level 30 for Blood and Wine
Blood and Wine is an endgame expansion. It is not meant for those just starting the story, or those who have found themselves halfway through and are looking for an excursion. The land of Toussaint is quite pretty on the surface, but is actually very deadly for those who are ill-prepared.
Starting at Level 30 will allow you to survive in the beginning, as most enemies seem to be around 33 when you first begin. If you find that you are much too early in the game, you can either be patient and play through until you’re ready or start the expansion directly from the main menu. The second option will provide you with a level 34 Geralt, but will lock you out of any Wild Hunt quests.