You'll get it, just keep practicing.

My buddy I've roped into doing Eroica with me had never had a bike with gears until 6 weeks ago. At first I thought he was a natural, then he started throwing the chain, now he's got it down and only last night did he have trouble again, but that was due entirely to the fierce crosswind. I also had balance issues going one handed to shift in that wind, but nobody crashed so success. If he can do it, you most certainly can given your love of bikes =)

I'd say the most important thing is to plan ahead and think about what you're setting yourself up to do.