Take it from a girl who's been there; length will not seriously weigh your curls down enough at the length that most of us would probably be comfortable will. Instead, having hair nearly all the same length will loosen curls. That's what worked for me, as my long curly hair was just slightly less curly and, since it's thick, unbelievably high maintenance, while now that it's around shoulder length and almost all one length the curls are looser and ill defined.
2Cish hair
Currently loving my Herbal Essences None of Your Frizziness