Yeah, the spinning thing. Many people believe that riding in a harder gear will help them get in shape faster. The only thing that does is cause knee pain. I try to pedal at 90RPM but anything over 60 will be fine. 80 is a better target that will come with practice. I started riding again when I was 43. The first few outings were really hard. Don't push yourself to get winded. Ride at an easy pace to go longer distances. Going faster will come on its own. You want longer and longer saddle time for the same perceived amount of effort.