There is a page! It's official from the school. Log on to the admitted students page and click on Useful Links. The link to the Facebook group is there. Congrats on getting in! Hope to see you next year for class of '17!
I'm afraid to join the official harvard group cause I don't want them to see my facebook! I joined one started by the class of 2016. Also my facebook name was changed for senior year so I'm not even sure if I would be accepted into the official group lol