Yes it is a gateway drug. You will gain the 3mph just by going with a group. The group will push (or drag in my case) you along so you will improve. Another benefit of a group is the availability of bikes to try or borrow. Most in my group have several types or makes of bikes and are willing to loan them out to new members to try them out. I started on my old MTB turned touring for a year or so, then moved to my wifes hand me down steel KHS for a year (a little to small for me but good for 25 miles or so with a group), then just this year got my own dedicated road bike. So don't get bike envy to quick and just enjoy the ride.