It's okay to pick your nose to remove the boogers or snot which helps to clear your nasal passages out so that you can smell and breathe better.
The boogers being removed by picking your nose also gets rid of bacteria and germs in your nose which is a good thing.
Just be sure to wash your hands really good with hot water and antibacterial soap to get rid of the germs and bacteria on your hands and fingers after picking your nose.
If you do pick your nose do not eat the boogers because not only is it gross the boogers can make you sick and eating your boogers is not good for your health at all.
It can make you sick although supposedly the boogers when eaten helps boost your immune system but the risks outweigh the benefits.