Heh heh, as someone who has been dancing and competing for over 5 years let me say that if you wait until you are comfortable with your dancing, that day might never come.

I'd say that if you at all feel like possibly starting now, then go ahead. Try one competition -- preferably a small local one -- and then you'll know for sure if you want to keep doing them, or if you prefer to take more time before trying another, or if you don't even want to compete at all.