Keep comfortable so you can enjoy it. At this time of year make sure you have nice toasty gloves on and avoid the puddles.
Listen to your body. If your joints hurt, especially your knees and hip then read up about bike fit. Most new riders have a cramped position that doesn't allow full leg extension which for me is important. Basically, if you don't almost straighten your knee on a down pedal your seat is probably set too low.
Your bum will hurt. Nothing you can do other than wait for it to man up. Cushioned seats won't help, but a pair of cheap cycling shorts probably will.
Do it as much as you enjoy it.
Look at strava to log your miles and plan routes.
Enjoy!