I second puttering around the neighborhood until you get familiar and comfortable with the bike, and then you can venture farther, but stay off the interstate for a while ;-).
March was a long time ago and you've probably forgotten a lot of what you learned so go slow, but don't wait until you've forgotten it all! That bike is begging to be ridden! Ride around the block a lot, in the middle of the morning when traffic is lightest. If you balance all right on a bicycle you should do fine on the mcycle, the key is to be moving ahead. You might want to just practise shifting from first to second and then stopping, downshifting and doing it over again. Baby steps, until you feel ready to go up one more gear. If it takes you a long time, so what? The main thing is to get out there and get on that beautiful new bike.