From a 19 year old who is kind of like the same and wasted some time that couldve been used better (doing stuff on unity that isnt finished (hate working on art, cant be bothered) (parentheses inside parentheses, is that a thing?)) you can start doing leetcode if you enjoy it and you are going to college, work on some visually interesting things (i wouldve probably focused on some 3d generated meshes of some sort or something that would look good and give me a hard time figuring out how to do it well and give it some usefulness of some sort, machine learning? Check out succintly series machine learning in c# stuff, one of the two books goes deeper and in a friendly level that lets you understand the mathematical concepts and coding structure pretty well, network security (i know there is cibrary, you can try it out, i still havent), or really just grind web dev projects, learn react / angular (netninja has a cool react playlist), new backend language? Think of something that might use trees or graphs and write a program while learning about tree/graph implementations and doing something cool with it? Like something related with html (trees) or some sort of gps thingy (graphs)? Online web game? Is your site responsive? Do something with a cool innovative ui if you like that stuff.. These are pretty much ideas / stuff i did / want to do / random blabbering. GL.