If i stretch my ear (not much, only a few mm) will it close up?

i'm a 17 year old girl, was thinking of stretching my ear, no more than like 4 or 5 mm, but i was wondering, if i decided i didn't want it anymore would it close up? i hear that anything above 6mm won't close but under that it will? also, could i put a normal earring in it? (if it doesn't fall out obviously) and would it look stupid having just one ear stretched?