Keep at the fitness then have another go, I say! My bike is also a 30+ year old Steel bike, and it just makes it all the more sweeter when you're waiting for half the folk on carbon bikes at the top of climbs.
Although poor show by the club member re. the Pinarello comment, hardly the best way to welcome newbies. I guess I'm lucky in that the members of my club ride a wide array of bikes from top carbon racers to vintage steel running period components! It's also worth mentioning that many quality steel frames weigh just as much (if not less) than modern entry level aluminium frames.