A school or university is just not a cramming machine. You may study at home too. The value of lectures over reading is that you get a sense of participation with other like you. Such a situation is also suitable for development of the personality. The class - room situation encourages debags and discussions and thus broaden the horizons of mind.
Some people are more social than others.
Sociability is an art which should be cultivated to grow into effective personality. Extrovert is a person whose basic orientation is towards external world. None of you fall on the extreme of the bipolar scale. Infact, most of the people have various degrees of the two types combined. In reality most of us are ambivert - the mixture of two.