Social insecurity ahoy! How do I fix a bad first impression?
Xmutex makes a good point, don’t read his comment as (only) jokey or snarky. I hate to come off advocating drinking, but: the reality is that, as you yourself describe, much of the awkwardness comes from your feelings of insecurity and, well, awkwardness. A moderate bit of social drinking, in my experience, will make you open up, which will make them open up, and soon everyone is comfortable and chatting away. The danger, of course, is that too much drinking can make you WAY TOO COMFORTABLE and the reality is that they may not all want to hear your extended exegeses on The Beatles vs. The Stones. Yes I speak from hard experience. Also: getting some good exercise right before the event can often really make things a lot more relaxed. You feel more confident and clear, I don’t know what it is but it makes a huge difference.