Should a 12 year old be able to go to the mall alone?

Most 12 year olds are more or less fully grown. In many busy malls, being a victim of a crime is relatively unlikely. A cell phone also improves safety. However, valuables are easier targets for pickpockets if carried in the back pocket or in an outer compartment of a handbag. You may want to check the crime statistics for the mall in question to be sure.