I agree with others, you'd be good on a 158. That said, don't get too caught up on it. I'm a lot bigger than you and I ride everything from a 154 to a 168. I can't rail on the 154 at top speed but I sure can have a lot of fun playing around on the groomers and in the park on it. I split my time between that and my 158 which is also fine in the park and lets me go as fast as I want on the groomers. When I feel like ludicrous speed is needed (cause light speed is too slow), I can pull the cambered 168.
Flex rating will also have a factor. A 158 wet noodle is still a wet noodle. :-D
Edit: And welcome to snowboarding!
Last edited by MeanJoe; 03-04-2014 at 12:25 PM.