Yeah a 150 is a little big for someone with your weight. Something in the mid 140's would be better.
Honestly the board isn't critical to learning. Get good fitting boots, and then see if you can pick up a used mid-range board around a 145-146 or so (a couple cm isn't going to kill you either way).
Especially if you're going to be riding a lot of park, you'll chew through boards like mad. Better to start on something used so you don't cry when it gets it's first ding!
I only say that because it's happened to all of us...