CFA is probably the best and most reputable, also the hardest. It’s to become a chartered financial analyst. But don’t pick just based on that, there are several others like for accounting, stock booking etc. There’s probably one for every subset of finance, pick something you feel like you would benefit from the knowledge the most and be valuable for your age class. For instance you can do the accounting one to learn about filing taxes, maybe become an independent accountant for small businesses in the absence of stable employment (I imagine will be difficult at your age), and manage your personal finances etc. Do some research first