We should never mandate a vaccine on younger adults and children for which we don't know the long term effects. Fifty (50) years or older? The risk of taking the vaccine is much less. You are likely not going to pass on any unknown side effects to offspring. But for younger individuals, lets give these vaccines more time (like 20 to 30 years) to determine the long term effects.
We will be a stronger society if we let the younger generation build natural immunities to COVID-19. Lets not introduce something new and not fully tested on the young ones. Use us old farts for that!