Kata is something that must be learnt from a qualified and knowledgeable teacher. Although books and videos can enhance understanding and aid memory, they are no substitute for proper instruction. Your instructor will be the most important person to help you with regards to your karate.
The important thing is how good the instructor can make you, as opposed to how good they are. You require a Sensei, not a bodyguard. Visit a number of dojos and look at the standard of the students, the way they are dressed and their attitudes to one another as well as to the instructor. The Sensei / Student relationship is a special one. If you find a Sensei with a deep understanding of karate and a genuine love of the art, and if you are prepared to study hard with dedication, openness and honesty, then you are sure to make good progress in all aspects of karate.