the flex would be fine for you, maybe a little on the soft side. all boot companies flex ratings are different, and i can't remember off the top of my head if tecnica ratings are generally softer or harder, but i think its softer. somebody correct me.
although i have to say, the agent 80s don't have the nicest liner or boot materials. you can find a better boot for the price. go to a boot fitter who skis the kind of terrain you do, or at least understands how you ski. they'll show you a few different boots that will work well for you.