If you are just starting out programming, then i would recommend python.
But you definitely want to know C. I think Rust is the future, despite the controversy. SO might want to learn that too. Don't learn C++ unless you have to.
Definitely C, but I'd also pick up at least some basic Python. It lets you do a lot with just a little code and a huge amount of scientific libraries which can be really helpful in STEM classes. It's also relatively easy to learn the basics of (it can be very complex but unless you're studying CS or software engineering you shouldn't need to have to dig that deep into it)
It doesn't look like there is one programming language that is the best to learn and you can be in trends all the time. Time changes and you should be up-to-date with technology. I'm a student of 3rd year of computer science and I study different directions and I haven't realized yet what final lang scope I keep for my future profession. You know there are so much subjects I have to go through at high school that it's impossible to follow everything. That's why I have to use edubirdie although it can be controversial for many of us. But hey, check https://edubirdie.net/blog/is-edubirdie-legal-or-cheating and the review will assure you that you can use this service and be focus on more essential thighs in your life. As for me it looks the most reliable but you can search for more. Also, if you have questions about guidelines in programming or something like different dev languages overview you can ask writers to help with this question as well.