After all the research we put into finding our target audience, we really wanted to target it at this audience and also in keeping with the brief given.
To attract both a male and female audience, as explained in other questions we decided to have female lead characters, as this will likely attract the female audience, which isn't as prominent for other mainstream films. Also the male audience which is already interested in the movie, could be interested in a new twist on the genre.
The age of the characters is something we also wanted the audience to relate to, as the protagonists were either 16/17 we wanted to really make the audience connect to them, by producing a really realistic story, that could likely happen and show their 'alter egos'. Rather than some really unrealistic story, where the audience could not relate to the characters.