Should I tri it?

The days have been pretty crazy around here. Business is good so it's difficult to complain but I'm going to anyway! A friend of mine really wants me to do a triathlon with her in October but I have had zero training hours in months. These days, I hike more than I ride, I walk more than I run. Still, it would be nice to work toward a goal again and to get in shape. Has anyone out there gone from couch (or desk in my case) to triathlon in a couple of months? I think it's doable if I CAN BE okay with just FINISHING versus unleashing that old competitive spirit and having a breakdown because I didn't do my "personal best". I guess, finishing at this point in my career and fitness would be a personal best right?