Want to make a personalized flash children's book - text fields and variables?

Hi there,
I’m looking for the best way to be able to have a user input their name, age, etc, and then place that data into a Flash Story book, to make it personalized. For Example:

Name:_____
Age:_____
BOY/GIRL:____

and then for example if the user decided to Enter: (Cooper, 7, Boy) the story would add those variables, so it might say:
“Once upon a time, there as a 7 year old boy named Cooper, who lived in flying shoe.”

Ideally, I would want to be able to have the text auto format so that it looks like a seamless paragraph, no odd line breaks or spacing issues no matter how long the name they entered was, so for example if they entered “Cooper” or “Cooper William Johnson III”, either way the text would still flow correctly.

Thanks for any help.