Listen, n00b -- the first several months, compare yourself only to yourself. If you start thinking that in two weeks you should be riding 50 miles a day with an average speed of 25 MPH you'll suck the joy out of this in no time flat.
Most posters here make up their times anyway.
Enjoy the rides. If you crave more, go on some local club rides. Then crush the local club riders, start racing, go to cat 1, compete in RAAM, give pointers to Lance, and so on, and so forth.....