i wasn't anything close to that kind of mileage, my best was a fast 7 miles/day, along with about the same in running/walking on a dirt track to build my lungs/endurance for ice skating. i wasn't a competitor in the usual sense, but a 'test skater', competing against the standards. did that for years, though i wasn't very good at it, i loved it.
what sort of bike do you have? mine was a peugeot mixti frame, that had been in a wreck prior to my getting it, so the headtube was bent in a little. no one could ride it but me, because if you didn't know the trick, you would wind up hitting your toes on the front wheel! but it was fast, and trappy, and i loved that bike,