I think most advice on how to start freelancing applies to you despite your age; it's just going to be a little harder for you than for a more experienced and/or older person. There's a ton of advice on this topic in previous discussions here. See https://www.google.com/search?q=start+freelancing+site%3Anew.... I think it's very doable though.
I'd also caution you not to focus on freelancing to the extent that it hurts your schoolwork. If you want to program as a career, graduating from a top 10 CS school will open a lot of doors for you, and I would make laying the groundwork for that your primary goal.
I'd also caution you not to focus on freelancing to the extent that it hurts your schoolwork. If you want to program as a career, graduating from a top 10 CS school will open a lot of doors for you, and I would make laying the groundwork for that your primary goal.