What ever system works for you, is the right system.
Is Haganah good? Yes, and so is Krav and at least two other systems I can think of.
I would go watch a class, and take a free class if it is available. I would also check out more than one school, as well as more than one system. See if there are Krav, Haganah and other systems taught in your area.
"If you're gonna be stupid, you better be tough."