Dear O'Abby: Is my book YA or Adult?

 Dear O'Abby,

I've written the first book in what I'm planning on being a series.  In this first book, my main characters are 15-18 years old, but as the series moves on, they will obviously age and as I've outlined it, they will be in their mid-twenties by the end of the series. Hardly YA anymore, but I'm pretty sure you can't change the category midway through a series.

So how do I categorise the first book?  Is it adult or YA?

Any advice you have will be gratefully accepted.

Kind regards,

Unsure

Dear Unsure,

Whether your book is YA or adult is about more than the ages of your protagonists.  There are a lot of adult books that are told through the eyes of teens or children.  YA is more about voice and the themes of the work.  

YA tends to be about self-discovery and the separation between children and their parents.  About firsts - first love, first sex, first break up.  About discovering who you are in the world as a n individual with your own thoughts and beliefs.

If your book deals with these things, then it is probably YA. If it doesn't, then maybe you've written an adult book with teen protagonists.  

Neither is a bad thing.  

If it's YA, you will just need to ensure that your characters and their journeys continue along similar paths in the future books as they do in the first one, that their growth into adults is natural and organic.  If you do it well, the teens who started with your first book will age with the characters and see their own growth reflected in them.

Hopefully that helps.

X O'Abby