To be a computer scientist you need as bare minimum a computer science batchelor degree. To get this, you need to meet the entry requirements of a university level computer science education. So the first thing to do check out some educational programmes in the subject and find out what the entry requirements are, and make sure you achieve those entry requirements at school.
You don’t need to know coding before you start, but it might be worth your while to learn one of the C-family of languages to a basic level, during your spare time. JavaScript is a good one to start with.