I hope cycling does for your life what it's done for mine - changed it in a very positive way.
The sky's the limit. When I started riding seriously in 2005 I was out of shape, and struggled to do 15 miles. Now my Saturday ride is usually 80 miles and I ride about half that on Wednesday mornings (when I start thinking I'm hot stuff I compare myself to happyslug).
I would encourage you to find a club in your area, mine is the San Fernando Valley Bicycle Club in L.A. I found a group of great friends who not only ride together but go out to eat (a great combination - you don't gain weight). You will get all kinds of great advice on places to ride, equipment, maintenance, etc. Best of all, you can "draft" each other - ride in each other's wake - which requires about 30% less energy.
You're welcome, and keep us posted. 
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