I don’t think you understand vaccines not only protect you but protect you from spreading disease to vulnerable groups.
Not everyone will be able to safely take the vaccine.
So, if I understand the point you are trying to make, it is that a 3 year old will be just fine taking the vaccine? Or is it that a 2 year old won't spread the disease to a vulnerable group?
Because the way I look at it is that people who are vulnerable should take the vaccine. People who have almost no risk shouldn't take a vaccine which was hastily rushed to market.