I'll probably avoid direct contact with my clone and watch from afar, I'm not really comfortable about being known by others, but since it'd be myself just in a different body, I'm not really sure. I know I'm good living with the 'me(s)' inside my head, but having them around me in real life is just freaky, triggers paranoia, and living with each other is just not possible (I know I am hard to live with), having sex with myself? as long as it's different gender and looks different (actually attractive) I might consider it, having sex is a bit harmless, unless I became addicted to having sex with my clone since it'd be sorta perfect and it turns into a weakness and my clone uses it to control me, or use other weaknesses to do that...but that really depends, because I might try the same, it'd be like an endless war or peace...neither I'm sure of....
all in all, whether I'd avoid that clone or have sex with it, I'm certain that I would want to have some sort of contact even if it was for the shortest while.
and If I met my 12 y/o self I'd probably hide, run or whatever, because if my past self saw me or moreover had contact with me, it'd be a changing variable in my past self, and that would change my present self which is the same as eliminating me in this time dimention and I'm not sure I want that.