I like the idea of them starting as adults but I'd lower it to college age (lower 20's) as a compromise between the school and adult world setting.
The European idea does little for me as I am not sure on the social stratus and gender cliques of different cultures. I lack the knowledge to write it.
One thing I'd like is the main character not to start with a potential opposite sex love interest in episode one. this keeps him from being tied down and allows freedom for him to explore his options without a default pairing forced on the story.
