What kind of time does one consider "good" for a marathon run? During Cross Country season I would run a 5 km course in about 20 minutes, and a 10 km in just over 40 minutes, but nobody who had just started running would keep that pace. I know Olympic runners can do 5 minute miles for each of the 26 miles, which works out to be over 2 hours, and you said you did it in under 4.
I'd like to run a marathon some time, during the peak of the CC season, I ran 10 km 3 times a week, with 5 km on the remaining days, so I guess I meet your criteria. It sounds like a great accomplishment, congrats.

Bo