She HAS to be 17, it shows that she is not yet tied and shackled to the corporate machine that many other Japanese are chanied to, thus has an optimism about her future that has yet to be crushed by social reality. She's not ready to sleep in her cubical and go home to a small, tiny closet-sized apartment and ponder her loneliness. That's why she's seeking a boyfriend.... most of the guys she knows are reluctant to talk to her, and are beaten by the machine to the point they just can't start up or hold a conversation.