I work at Safeway. I m 16 is it ok for me to be missing work?

Only if you have a good reason to miss work such as an illness, injury or death in the family.

Not without good reason. Missing work speaks of an unreliable person and you would be first on the list to go if staff were to be cut back. Also they could not give you a good reference stating you are reliable and trustworthy

Not if you want to keep working at Safeway.