A very good friend of mine created her Facebook account just a few weeks ago, and I still think she's cool. So getting into the game late is at least sometimes recoverable from.

Adding everyone you are even tangentially acquainted with seems to be the social convention, including people you've just met; it's common for me to receive facebook invites after meeting someone at a party, for example.

FB has some tools for bulk-link-farming... e.g., it will look at your email if you let it and contact everyone whose name appears in it who has a FB account. I did this when I created my FB account (a couple of years ago) and it worked pretty well.

As far as I know, there's no way to hide your friends.

The teenagers of my acquaintance frequently use fake names on Facebook to subvert searches. The adults frequently create multiple Facebook profiles, more or less for the same reason.