There are a number of nappies that fit from newborn (4kg) to TT. I think it's best to wait and try at least a few brands first. Some nappies just don't work on some babies... due to chubby or skinny legs, or other reasons.

Having said that.. they do have reasonable re-sell value if you find they're no good for you. But it's up to you.

and YAY for going cloth!