Some people think you are where you came from. I used to work for a woman who introduced herself this way, "Hi, I'm D____ S_____, I grew up in ______________ and my family has farmed their land for over 100 years." She'd beam then, satisfied with her place in the constellation of life.
That summation made me grit my teeth.
What about the person she'd become in the many decades since she left her parent's house? Our business prospects didn't care about her past, they wanted to know whether she could help them today.
I'm in the middle of writing Chapter 20 of my first book, a murder mystery. The end is in sight. But at the beginning, before I knew I could write a book, I had to find the points of the star from which the lines would come--an opening, a death, a killer ending, and...characters.
How do you create a whole person from nothing? I wrote down their childhoods, where they went to school and what they studied, the kind of work they did, the families they created as adults. Their passions, their faults. The hard bounces they'd taken from life. The choices they'd made that formed them into the people they were when the book started.
Virtually none of that is in the book, but it informs every page. When I sit down now to write, I know the people and I let them take the scene where it needs to go, in their way, in their words.
They're still writing their biographies. I like that idea. I'm still writing mine too.