Programming Skills Depleting

When I was in SkillsUSA back in high school (Darn, I need to stop relating to school like it was so far back then), I use to be the best in my state. I would reverse engineer things of the same language and then build them in a much more simple manner. Nothing too bad, but small things like java made save editors and stuff like that. After doing so many, I realize its easier to reverse engineer something relative to what I need to do to learn a language and refresh on the ideas. For instance, I started building GTA FiveM mods. I would take other peoples resources, read them and try to generalize the code using my own knowledge.. After about 3-4 scripts I started to write things that other server did not have. Now, I look back and it's almost like reading a foreign book. I can understand what it says to an extent, but I don't know where I came up with a lot of the content lol.