There's a chart that gives you an approximate ideal flex based on your known height and weight:
http://www.schoolyardpuck.com/2010/0...tick-flex.html
EDIT: Seems they changed the link with the site maintenance, haha.
It suggests the ideal for you is around an 85 flex. Obviously people have differing preferences beyond this, but i guess it's a good guide to what you should be looking at. I haven't bought my first stick yet, but i've tried the 65 flex intermediates (supposedly the stiffer end of the ideal for my height/weight) in the shop and they feel great!