Man, your sister is me five years ago. Here's the fix that ended the burnt garlic problem for good: grate or microplane the garlic instead of chopping it, then stir it into the oil off the heat or right at the end. Bigger chunks sit in the hot oil and scorch on the outside while the inside is still raw, and thin garlic cooks through in seconds. Also keep a splash of water or soy sauce ready to kill the pan temp the second it goes in. Garlic early can work, but only if you treat it like a ten second job, not a base layer like onions.

The thing that unlocked it for me was learning that variables are just labels pointing at stuff, not boxes holding stuff. Once I got that, I stopped being scared of passing lists into functions because I could see when I was handing over the label vs making a copy. That one idea fixed half my weird bugs where stuff changed when I didn't want it to. Did the Austin tutorial get into that at all or was it mostly about functions?