What to learn: build a foundation in coding first. I suggest python but its really up to you. Youll also want the theoretics of coding like why we use it and what it is and the ethics of it so on and so forth.
Starting a business: This comes when you find the pieces that go together to make it happen. Youll find a service or good that you can offer to a target audience and then work to brand this thing that your selling so it stands out from others and looks lucrative. Youll want a team that can help you build this business into a success. Look into the basics of entrepreneurship and business management for more details
Why computer science: It will give you real skills that you can apply to projects and life in general. Yes soft skills, like leadership or communication, are important but you still need hard skills as well. The corporate world is oversaturated with middle managers with MBAs that lack hard skills like actual coding capabilities. Being able to do both shows your employees you can understand them, help them, and “talk” to them in a way someone lacking those skills cant.