He had a bicycle. She was 7 years old.

Other details are absolutely irrelevant. A means of transport is always useful.
She. Well, she was 7 years old. The most important age, for they showed how well-behaved she was. She would always greet one with a smile and utter the sweetest 'thank you' and 'please'. Nowadays, one does not get to hear  'please' so often as one used to!
Therefore, they were both rich. He knew how to pedal, and not even once did he fall down from the bike. That is, of course, ever since he learned how to ride it as he was 4 years old.
As a matter of fact, the years were her fortune. She had lived them intensely and fruitfully. She knew how to recite poems and make shoe laces with ribbon. But most of all, she had learned to refrain from sticking her tongue out.