This is a great question! I'm a recent college graduate who majored in accounting and finance but when I first started, I was just as eager like you to learn as much as I can about finance/investing. A major reputable platform that can give you access to most financial securities with zero trading fees is called "Fidelity". Before you decide to invest any of your hard earned money though, I would recommend that you learn as much as you can in your coursework regarding finance/investing. You never just want to blindly invest money into companies. On top of all your school education, some books that I would highly recommend to you that would certainly further your knowledge on finance/investing concepts include:
- The Intelligent Investor by Benjamin Graham
- One Up On Wall Street by Peter Lynch
- Stocks for the Long Run by Jeremy Siegel
- Unshakeable by Tony Robbins
I hope you can find this information to be helpful! Good luck with school and your future career in finance my friend!