Welcome, Hannah! I am new too, but I'm the flip of your age -- 61. There's another teenager who posts here and on YouTube, @cryptonick. He's kind of a superstar in the crypto world, so you should check him out. I think he is also 16.

As for those languages, Spanish is the easiest of the lot, because many words resemble English words with Latin roots, and the grammar is similar. Plus, you can find Spanish-language TV and magazines all over the USA. Russian grammar is difficult, from what I have read. Arabic , too. I work in China, and I'd suggest you try to learn spoken Chinese first, using the pinyin writing system, then when you get some basic vocabulary, learn the characters bit by bit. You might even find a native speaker in your community to be a tutor. Plus, YouTube can be a great resource.

The US government has designated Russian, Arabic and Chinese as "strategic languages," meaning if you can learn any of them really well, you could probably get a government job easily.

Anyway, good luck! I'm following you now, and hope to read more from you.

Oh, and BTW, I used to be a high school physics teacher.