So as soon as you learn to talk, you can handle every social situation adequately? That’s news to me.

No, they didn’t say that, they said that knowing how to talk is the only prerequisite. The rest comes only with practice, the sooner the better. Anxiety’s a bitch, I get it, but you make it manageable by desensitizing yourself to those situations (preferably starting with the low risk ones like introductions), not avoiding them.