Facebook Privacy - Are Your Old Posts Hidden?

Having so much of your personal life online can be a bit daunting sometimes when you realise just how much information people can find out about you. I admit, I'm on so many social sites that you could piece together the history of my life if you looked hard enough (thankfully the Harry Potter film Director takes over the majority of the David Yates Google search results haha). 

Where I draw the line is with people being able to look through my Facebook history. The account is linked to so many members of my family and friends that I need it locked down. Now we all know about making your account private, but I recently discovered this may only apply to future posts and that strangers still may be able to view any posts/photos/videos you have in your history. If you go to settings > privacy, you will see a button which makes all old posts limited to your current security setting. Mine is only allowed to be viewed by friends, and so now only my friends can view my posts - even the ones dating way too far back when it was popular to like a thousand different Facebook groups, and poking was a popular function...