It is no good becuase it means u will age faster than your numerical age.
girls want to look mature when they are young, they put on make up, wear heels, push up bras and what nots, but as time goes by, they try to fight the power of mother nature, botox injections, endless facials, more make ups and etc...isn't it ironic?
Not good. You're maturing too quickly and your tits will start to sag when you're REALLY 20. And might be touching the ground by the time you're 30 (If they're big enough anyway)