Hello, it's not that a girl becomes cold after going to college, but that you are not familiar with her. You are strangers to each other and don't know you, so you think he is cold to people. Maybe you think her appearance, plus you don't know each other well and haven't talked to him, you think he is cold in your impression.

With strangers, of course, people you don't know have nothing to say. Seeing others makes people feel cold. In fact, when you get to know a person and get along with him, you will understand his true character.