I would recommend staying away from technical analysis. When I was around your age I was convinced it was the best way to invest. At best it is good for viewing past trends.

Becoming good at understanding basic accounting and corporate finance principles are more important. Then you build off these to from your own investment strategies/views. Also, a good understanding of micro and macro economics is important. I bought two used textbooks when I was your age and took detailed notes. Most of the knowledge I have today is from that despite taking AP Econ.

I also went to college for finance, and I think the fundamentals you learn are very important. I now work at a marketing technology company, as I have some ownership in it, but a lot of my time is spent managing my portfolio. Which right now is market shorts and treasury bills.