I'm witing a story about a boy and girl that meet at the age of eight. The story covers until they are in their early 20s. It's written in 3rd person, but I've been strongly advised to write it in 1st person. My thinking is to write the boy in 1st person, and the girl in 3rd person, probably alternating the chapters. My question is: Should I write the boy in 1st person as he ages, or write him at an older age, looking back and telling the story.