What should I know before starting my first Karate lessons?

Hi there ! A couple of days ago i was just looking in on what self defence i should know and what would be the best one for me and i heard that karate is a very popular sport in my country and so i thought i would start it because a lot of my best friends from my school do it and say i should know it because its an excellent self defence and so I wondered if there's anything i should know before starting it. : )

What should I know before starting my first Karate lessons?
Post Opinion