which city to study chinese: shenzhen or guangzhou?

Hey guys have a nice day! I'm planning to go China in this september to study chinese course for a year. I already have hsk 4 certificate and i wanna improve my chinese. Also i want to learn and study about import export and logistics. But I have two options: Guangzhou and Shenzhen and im really confused which one to choose. Is there anyone in one of this cities studying chinese to help me to decide?