As we understand this article:
Fever, aches, headache from the virus = BAD
Fever, aches, headaches from the vaccine = GOOD.
If you're younger, you're LESS likely to have serious symptoms from the virus, but MORE likely to have "robust side effects" from the vaccine. " It probably has something to do with how intact the immune system is for younger people,” according to Dr. Jason Farley.
That means the vaccine is working!
But if you don't have any side effects, that doesn't mean the vaccine ISN'T working, even though that's how you can be reassured that it IS working.
It just means it may be "normal" for you.