Is Introversion and extroversion a real thing?

People can be what you might call introverts with a capital I (aka "very introverted") or they might be outgoing in some situations with some introverted tendencies. Introversion exists on a continuum with extroversion, and most people tend to lie somewhere between the two.

Is being an extrovert genetic?

Extraversion is highly heritable, implying that it has a genetic basis. The fact that people still vary on the extraversion continuum implies that natural selection could not deliver a clear verdict for extraversion over introversion.