I have never let others know me, just for fear that others will know me too well. How can I change it?

In society, as an individual, it is right to be prepared, but you may have gone too far. People live in groups, people are group animals, and the relationship between people should not be too distant. You alienate your classmates, don't like to let others get close to you, don't know yourself, and always keep your own inherent personality. This is unacceptable. You know, classmates always like to ask you personal questions, not because they look down on you and want to take the opportunity to laugh at you. They are just curious about your behavior (I thought you were different from others). You should get along well with your classmates while maintaining your personality. Maybe people think differently about you. Let them talk, just be yourself. Sometimes people who look down on others should be looked down upon, right? You can ignore this kind of person, but after all, there are still many classmates who can get along well, at least much better than you are always alone.

Don't worry, you will find that being understood by others is actually quite beneficial.