Jump on the bike and hit the road! The park sounds like a good place to start. If you've been on a stationary, you'll LOVE being outside and the change of scenery. As for how long - do what you're comfortable with. Don't over-do or you'll probably not enjoy it as much.

But in addition to the helmet, you're going to want some cycling shorts. Check out Team Estrogen's site for a great selection in every configuration and price range.

And don't forget a water bottle! Hydration is really important.

The biggest thing - enjoy yourself!