I don't think a 14 year old can get money for that.
Unity Learn is free: https://unity.com/learn#explore-how-you-can-develop-your-skills
You can try starting with this one: https://learn.unity.com/course/getting-started-with-unity?utm_source=learn_recommendation
Yeah, I know. Just saying that it is the easiest way to learn without taking much efforts, because of how not easy it was to properly learn a least something for me, I gave up a lot of times, and this tutorial finally dragged me trough that! Not saying I learnt a lot but it was enough to create something and move on on myself! I think 10$ is not that much!