It isn't too early to /think/ they are safe (a subjective judgement since they do harm a small percentage of people, just like the debate whether the virus is 'bad' or not). It is impossible to know with certainty if there are long-term effects, and predictions made from past events are obviously uncertain.

Is this a standard that you've applied to all medical care you've ever received, or is this particular to this vaccine? For example, have you ever taken medicine or received a treatment that was invented in the past 50 years, and if so, why didn't you feel the need to wait for an entire human generation to go by first?

Treatment is usually for a condition that is acute or severely altering one's quality of life. The calculation is how any unknown long term sides weigh against the immediate danger or reduction in quality of life. It is an entirely different calculation for a prophylactic that may have unknown side effects.