I wondered how I can know when I joined Facebook.
It is easy to know..
With this you can even know about:
- Your profile information (e.g., your contact information, interests, groups)
- Wall posts and content that you and your friends have posted to your profile
- Photos and videos that you have uploaded to your account
- Your friend list
- Notes you have created
- Events to which you have RSVP’d
- Your sent and received messages
- Any comments that you and your friends have made on your Wall posts, photos, and other profile content
For all this you need to go to:
Account > Account Settings > Download your information
You can find more information at:
https://register.facebook.com/help/?topic=download