My first sci-fi book, I read in '86 or '87.

It had a group of young people on a spaceship. The backstory included something like... the humans were living on Earth in 'ancestral' type group (or maybe some other type). People with the greatest intelligence or ability were 'taken' and that is how all the young people came to be in outer space.

There was something about a group/council that controlled everyone, and a ring.  

One of the young people was very good at math/computers and ended up integrating with the ship.

Not much to go on, I've been searching the web on and off for two years now.