Well that's a lot to deal with. I'd say that you are thinking too far ahead. Set smaller, more reachable goals and work up.
I don't know what you're comfortable with. But say you never talk to anyone. For example, this week, make it a goal to say hi to 5 people a day. Or good morning. People love it. I've never had someone say hello or good morning and been offended, even if it was a bum on the street it still feels nice. Next step, throw a question in, beautiful day isn't it? Crazy hot out today huh? Get some harmless diaglogue going. Start small, most people enjoy a friendly interaction with a stranger. If she doesn't, the worst she'll do is to respond hastily with little or no indication of wanting more. No harm done, and you've moved in the direction of chatting her up.
Eventually If you have a few experiences where you're having a nice chat with a woman, and you for whatever reason don't ask for a date. Your mind will go to that later and you'll be kicking yourself. Then it will be that much easier to overcome any "fear" the next time you're in that situation. And keep in mind that fear is just adrenaline, just a chemical, and those chemical levels change even if nothing at all in reality changes. You probably know that by now but it's always good to remind yourself.
