You got a mixed bag of advice, some of which must seem scarey because of the way it was posed... I suggest you search for "munch" in the library and hear the absolutely positive reports several other new-to-munches forum members have had.

angelic zest for one... had exactly the same concerns and nothing but positive things to say about her experience.

I am a hearty endorser of going to munches. Just be yourself, but if you tend to be shy, you should push yourself to talk to at least one person... and let yourself be introduced. You will undoubtedly be welcomed with open arms and made to fee comfortable.