SOLVED. YA Dystopian series. You die on your 18th birthday. No adults in the story. Read 2004-2005. [s]

[K]

I remember the books were short paperbacks, no more than 200 pages thick.

I think one of the kids lied about their age (to seem younger), and on their birthday when they reached adulthood, they like disintegrated or melted? There were no adults in the story, as they had all died.

[Rainbowheart]

The Countdown series?

The first book is January.

[K]

That’s it! Thank you so much!

[Rainbowheart]

Awesome, glad to help out!