You know the phenomenon where you learn something new, and it feels like the most obvious thing in the world? Why did nobody tell you that you should choose subjects in school that you enjoy? Why didn't you figure out sooner that your parents are adult humans who also make mistakes? How could younger-you not have realised that getting dehydrated is what makes you irritable sometimes? It's all so clear now! You mention it to your friends, and they're surprised: they realised the same a year ago, and assumed everyone else already knew. It's so obvious, after all.
The worst thing is that you know that in another month or another year it'll be something else. Experience is a horrible way to learn. Advice columns in teenage-girl magazines are marginally better, but you really don't want to be seen buying them. Here's an alternative: share your newfound wisdom with other people who'll appreciate not having to learn for themselves. It's the sunscreen song for an older audience. Tell us what you learned.