There are dozens of threads on these forums that will help you to make that decision. I personally prefer MySQL although in saying that I have only ever learnt MySQL, and I can guarantee you that lots of people also prefer INI over MySQL.
I believe that if you are new to scripting that INI is generally considered easier to learn and become accustomed to.
I would suggest that you read over some tutorials for both INI and MySQL to help make your decision, you can determine which one you feel more comfortable with.
MySQL: https://sampforum.blast.hk/showthread.php?tid=56564
INI: https://sampforum.blast.hk/showthread.php?tid=50
(Please note: There are multiple MySQL and INI plugins available, I have simply listed the first that I could find as an example.)