Oh wow, you will be busy! I am also expecting twins, but these are my first, so I will not be quite as busy as you! I will probably be clueless though, since I've never even raised one baby, much less two at once, lol! I'm 16 weeks, and my OB said she won't let me go past 38 weeks, which would be Nov. 11th.
Congratulations, you must be super excited!!! Good luck :)