I just completed high school. I love coding. I heard about competitive coding. But never knew where to start help me please

Question

tell me where to start ... which language to choose.... and so on...

Answer 1

Are you asking how to learn programming or how to compete against people?

https://www.codewars.com/
^That place is a lot of fun.

If you're asking where to learn, then... you're already on a website for it. Good place to start.

Elaborate upon your question and I'll help you further.