Possibly the Everworld series by K. A. Applegate. It's YA and it's about teenagers and it's fantasy and it has Ever in the title, which meets most of the admittedly limited criteria!
David's life was pretty normal. School. Friends. Girlfriend. Actually,
Senna was probably the oddest aspect of his life. She was beautiful.
Smart. But there was something very different about her. Something
And on the day it began, everything happened so quickly. One moment,
Senna was with him. The next, she was swallowed up by the earth, her
screams echoing from far, far away. David couldn't just let her go.
Neither could the others. His friends and hers. So, they followed. And
found themselves in a world they could have never imagined.
Now they have to find Senna and get home without losing their lives.
Or their minds. Or both...
Published in 1999 so the date range is also close.