How good do you need to be to play online AOE2?

I'm sure this is a common question. I'll start by saying that I know that when I first go online, I will lose matches and my rating will lower until I am with players my own skill level. My question is, more specifically, what does this bottom level look like?

Do I need to know every civilization's bonuses and weaknesses without looking, or will the time I spend looking at those charts in-game not amount to much of a disadvantage at the lower levels? Do I need to know every counter for every unit? I have only played AI before and don't want to be too far behind the ball when I start on voobly.