I've always looked at Introversion/Extroversion using the battery example. As an Introvert, we recharge our battery by being alone, and drain it in groups. An extrovert is the opposite... charge in groups, drain when alone.

Outside of "charging your battery", it's a matter of skills and preferences. You can learn to deal with groups better, and (when allowed) pick the events you want to deal with.

If those meetings are important, don't avoid them. But if they are "social gathers because someone wants you to go"... then you can think twice.