I was 14 and my brother 12 when my mother started studying in the 80's.
It sounds to me as though your children are already involved in the religion. They have friends within the religion that they will lose should they decide to leave it.
For me, within a few months i was 'encouraged' to stop hanging around with school frineds and only mix with congregation kids. At that age you're impressionable, i looked up to many kids in the congregation, there was alot of youngsters my age and a little older. Eventually when all of your friends are JW's and both you and they are told to only mix with congregation kids by parents and elders then you are trapped and just can't leave.
I also believed at that age through bible study with JW's that i will die at Armageddon, which was coming shortly if i didn't carry on with my studies.
As a kid with a very high IQ i left school with no qualifications and did a menial job so that i could pioneer. But everything was great because all my friends were pioneers too, so we had a laugh.
Eventually as an adult once i realised that i had been taught wrong and wanted to leave i had to leave all those friends behind.
I hope you find your answers here.