Don't think too highly of friends. Finding validation/worth in friends or a significant other.
You have to learn how to be able to be alone. Don't get too attached to others.
Trying to fit in. Whether you do fit in or you don't, it's temporary and can change up. Same people by your side right now, will likely betray you later.
Learn the difference between a guy saying " we are dating" (him saying he is your boyfriend) and assuming that means you are in a serious relationship. The idea of a relationship and dating is defined differently from person to person.
Speaking of which, don't let a 'relationship' with no clarity be a reason have sex or rush the sex. Do it completely because you want to.
You try to grow up fast and it will catch up to you. You put yourself in adult situations as a youth and you will get treated and dogged out like an adult.
Don't give anyone more than what they give you. In a friendship. Interest in romantic relationship.
Don't get weak by hearing the word "love" from someone you may just be infatuated by. The word is thrown around loosely. A lot of times to manipulate.