I don't know what to talk about, but hey!
Hi, and welcome! I'm sort of the reverse of you - old in bod, but young in mind. Some things you might want to do:
1.) Read the site policies and FAQs, especially those relating to Mature and Adult Content in games, and how creating duplicate accounts ist verboten. That step will save you headaches.
2.) Hang out in Community Chat for a while, and get to know the place. This is a great way to meet folks and get a feel for the community.
3.) If you want to run a game, you'll want to look at the GM Help. Don't be afraid to ask questions if you need to, but it helps when you do if you've done your homework.
4.) The forum Game Proposals, Input and Advice is a place to float new concepts to gauge interest before doing the work needed to put together a game. When you get ready to seek players, the forum Wanted - Players is the ticket.
There are lots of other places to go for information and for fun. Over 4,200 games are hosted here in a wide variety ranging from old school to full-on d20, homebrew, free-form and more. There are lots of great folks, players and GMs alike, waiting to help you get your start.
What are you interested in playing or running?