Self Studying AP Micro

Hello. I am currently a senior taking AP Macro at school, and I heard that if you take the macro AP test, you can take the micro test under the same fee. Therefore, I want to self study micro to get some more college credit. Is this a good idea? Is there much overlap between both econ classes? How much would I need to prepare for micro (keep in mind I’m learning macro)? Please leave a response as I would highly appreciate it.