Older kids can be great - but I would talk in-depth and read ALOT before jumping into that.... it is tough tough tough - but do-able. If you have any other kids at home - you have to be careful about interupting the birth order and you have to know if the children you are bringing into the home have any history of abuse which they could pass on to your child/ren already at home. I have read that about 25% of older child adoptions are disrupted (meaning the adopting family finds a new home for the child and the new family adopts the child).
It is true - the older they are the more issues they CAN have - not all do - but most have some issue that must be dealt with immediately or your home will be turned on its ear (will be anyway if you bring home 2 girls)
Good luck - just be prepared for a rough ride initially - but eventually most do well.