I can relate totally to what you are saying. I was 27 when i left the organisation, prior to that i'd had no real interaction with anybody outside. I didn't know how to mix or socialise with anybody, where do you meet them? What do you talk about? It was a big learning curve, i watched others and saw how they did it. Find yourself a friend and start going out, meet as many new people as you can. Even talk about your experience as a JW if you feel comfortable with it, you'll find that people in general are interested in it.
You've just got to put yourself out there and go for it, no matter how scary that may be.
Paul