Trying to find the right board

[Janellope]

I am looking for a shortboard, but I keep getting conflicting information. I live in SoCal (3-6ft waves) and I have been surfing for about 3 years. I was riding a 6'4" and I liked it, but it was too big for me (Im 5'4"/145lbs). I would consider myself and intermediate surfer, but some people tell me to get a 5'9" or so. Does anybody have any advice on what size of board I should get? I like a board with more of a rocker than a flat one, and also one thats about 2 1/4 thick (it makes it easier for me to duck dive with).