Standard n00b fare: ride a little at a time until your tissues toughen up. Don't worry about distance and speed for now. Don't expect to be a ball of fire for 2-3 years. When you want to get faster, ride with a club. Read a lot, dismiss about two thirds of it. Ignore all posts about average speed. Buy a new bike whenever you want to if you can afford it. If it doesn't work out, list it on Craigslist and make someone else very happy.

I think that's it.