Yes, and for the runs you listed as planning to advance to ... you should get yourself into the Karma S (it's rated for up to 155 lbs). The Karma is the best whitewater kayak ever. Coming from the Zen, you will love it. I'll be posting a complete review of the Karma on Four Corners River Sports blog soon, but talk to them and get yourself the Karma S for enjoying your growth and class IV-V pursuits in kayaking. Congrats on loving the sport. Fell free to contact me if you have any questions.
No risk, no reward. It is not that we have to, it is that we get to. Preparation and education are essential to self-confidence and success. - KV
"If there is no risk there is no adventure."- Bill Briggs