Agreed about Roblox!! Started (unintentionally) teaching myself how to program on Roblox when I was 9, and turned it into a career! Making games encompasses so many areas of programming/creation. Even beyond programming (back end, front end, UI), music composition, sound effects, animation, design, game design.. and share it all with your friends. Alternatively, a simple engine like Love2D (which also happens to be Lua)