Do you have to know how to ride a bike?

Hi Peace Corps folks! I'm 22 and have been considering joining the peace corps for a few years now and absolutely love the idea now that I've graduated. The one thing holding me back right now is that Ive never been able to ride a bike. I tried to learn when I was younger, but never got the hang of it and now the things just make me panicky and borderline nauseous. Is there any other way to get around in whichever country they place you, or is knowing how to ride a bike absolutely necessary? Follow-up question, are there any countries in which biking isn't the primary method of transportation? Thank you in advance!