Find someplace that has a big selection and feel out different poles. For your height/weight and speed, I’d start with a 14’6″ or 15′ 180 lb pole – don’t worry about flex #s at this point.
Start your grip at the highest you can grab and straight pole from a 12 step run-up, then keep inching the grip up until you have to hit a firmer plant and bend the pole. Grabbing at 14′ should do you just fine.