Most days it will go great. Some days you'll get a flat in that shady part of the woods where all the mosquitoes hang out. Other days you'll ride into a headwind in the morning and it will turn around and give you a crosswind on the way home. And other days you'll forget to pack underwear and have to go commando (It happens to all of us at least once).
Don't worry about the unknowns. About half the things that don't kill you will make you stronger, the other half will make you wiser. Anything that does kill you, you won't need to worry about a second time.
As for the routines, etc. those you pick up by trial and error. You can learn a lot by searching through the old posts in this section of the site.