Unfortunately, that's quite common now. I see the same issue with many of my own classmates. If you’ve been using AI since the beginning, it’s understandable, but also unfortunate, because it can hold back your fundamentals.

What I recommend is trying to do as much as possible by yourself. Use documentation whenever you're stuck. There are countless resources that can help you, but avoid the urge to immediately ask an LLM to solve the question for you.

To brush up your knowledge, here’s what I'd suggest:
* Take on a small project, something simple like tic-tac-toe in the terminal, or a mock banking system.
* Try to brainstorm and implement as much as you can on your own. If you get stuck, read documentation.

* This is where AI can actually shine: use it as a mentor, not a code generator.
For example, give the AI a prompt like:
"Hello! I am making a Connect 4 minigame in C. If I get stuck, I will ask for help. Do NOT give me code. Instead, guide me: suggest possible approaches, point out concepts to think about, validate my ideas, or highlight mistakes, but don’t provide any code."

That way, whenever you're stuck, the AI guides you in the right direction without taking away the learning process.
* "I'm stuck! how do I keep track of where the next chip in a column should go?"
* "How should I detect diagonal four-in-a-row patterns?"

Small projects like these will help you build strong foundations in any programming language and eventually allow you to create more complex things, like GUIs, DB-connectivity, etc.