One other thought I had about this recently - talking to people who are very young about FIRE is hard because even if you're diligent it usually takes a long time!
My experience was that DH and I saved on blind faith for a while even though ER seemed impossible. We pretended we were saving for a temporary work time-out instead because that was more tangible and believable. When things came together for us a few years ago and I figured out that our ideal FIRE scenario might be possible, it was a whole new ball game.
The same thing just happened with my sister this weekend - we were working on a revised savings plan for her, and because of some new circumstances, FIRE is suddenly in the realm of the possible. She was saving anyway, but it really renewed her motivation and let her see the (still distant) light at the end of the tunnel.
So my thought is to maybe not focus on FIRE so much as the fact that saving up any substantial amount of money will give you some choices - take a year off, work part time for a while, whatever.