What happens to current library if I join a Shared Family account?

[mgpg89]

I'm currently enjoying my own account & library, but now my dad says he wants to get a family account for the four of us.

Simple question: what will happen to my library if I join a Shared Family account, but still with the same e-mail address I'm using right now?
Will I have to start over with a new library or can I just keep using it as if nothing happened?

And another question for the future: what will happen if I decide to switch to a single account a couple of years down the line?


Thanks in advance