Facts were taken right from NANA 7.8

Osaki/Oosaki Nana
age: 20/bloodtype: A/height: 162cm/weight 43 kg/
The lead singer of Blast!/Blackstones. She is strong-willed and she knows what she wants to be-- a successful singer that would surpass Trapnest. She is confident in her actions, and a little rough with her words when it comes to her friends-- she pretty much abuses Nobu.

Komatsu/Koumatsu Nana
age: 20/ bloodtype: B/height: 158cm/weight 46kg/
A typical girl with a kind heart, although somewhat clingy. Oosaki jokingly calls hers Hachikou, teasing her that she's like a puppy-- obedient and eager for attention. Hachiko is quite boy-crazy and easily gets crushes. Despite her ditzyness, the girl has real insights, though her heart is definetely bigger than her brain.