Honestly, going to university helps you with stepping out of your comfort zone. In high school, you're peers with people very similar to you (especially if you go to a selective school, everyone is very academically gifted, depending on where your school is located there may be majority ethnic groups). Introverted was the best adjective to describe me during high school, but university kind of forces you to interact with pretty much strangers when you first meet them, but over time, you get to build friendships with these people