Hi, dear you have not mentioned your age and gender.
I guess you are some where around 13-18 years and started developing hair on upper lip
As such there is no specific age when we can start shaving, it can be done any time but at least you should be mature enough to handle razors.
For sun tan you may apply a broad spectrum sunscreen with UVA and UVB coverage during the day time.
It has to be repeated every 3-4 hours.
Aviod being in the sun as much as possible
Try to wear full sleeve clothes as they protect from sun rays to some extent.
You may apply pigmentation reduction creams by prescription from a dermatologist
Hope this helps you.