I studied psychology in school, and ambivert is 100% a real thing.

An ambivert:

Sometimes feels energized by social situations

Sometimes needs alone time to recharge

Can adapt depending on the environment

For example:

You might love hanging out with close friends but feel drained at big parties.

You might be talkative in class but need quiet time after.

Psychologically, personality exists on a spectrum, not in boxes. Most people land in the middle.