Lose all of my memories, because i'll be able to do and try things I wouldn't ever have done because of painful, or embarrassing past memories. And because if I did something like confessed and got rejected I wouldn't remember.
I'm 13 (almost 14, so excited!) and I have a long way ahead of me so I'm not sure yet. I can probably decide when I'm older because all of my old memories are the best and my new ones I don't know yet because I haven't gone through my future Lolz :)