I've always heard that your knees should never go past your toes when squatting but lately I've seen a lot of coaches saying that's actually normal. Now I'm confused about what's considered good squat form. Should I be trying to keep my knees behind my toes or just squat naturally?
Bro for most people it's completely normal for the knees to travel past the toes especially if you're doing a deep squat. What's more important is staying balanced over your feet.
If u force ur knees to stay behind ur toes u often end up leaning too far forward which can put more stress on ur lower back.
Everyone's body is built differently man your leg length ankle mobility & stance all affect how your squat looks man
Recording your squat from the side can help you spot issues man like your hips shooting up or your chest collapsing give a try you will know what exactly to correct 
The biggest thing is that the movement feels controlled. If your knees track over your toes naturally and you don't have pain you're probably doing just fine. 
Focus on keeping your heels planted and your feet stable. Good balance matters much more than where your knees end up and work on your ankle mobility if your heels keep lifting. Limited ankle movement can make squats feel awkward.