Work Parties and Other Oxymorons

What does everyone think about work parties? I’ve never really experienced them, and they always seemed weird since I’ve never really worked with more than one person who was in my “peer” group (within 5 years of my age and same station at work as me). Plus, most of my companies haven’t had them at all and definitely not traditional work parties.
My new job has them a few times a year, including a big party every July. The big party is Friday, and my new manager invited me today. It’s actually a huge event – not just the company – so it won’t be too awkward to not know anyone. It seems like a blast, and I’d love to go. I just wish I’d started sooner. I’m not sure the first time I meet people that I want it to be at a place with a bar (not that I’ll be getting anything approaching drunk, mind you). Maybe I’m just old-fashioned.
So far, I‚Äôm 85% sure I‚Äôm going because I do want to, and I am eager to meet more people. But I am nervous. Maybe I‚Äôll feel better tomorrow once I pick up the tickets and understand more about the event, what to wear, etc. I think I’m more nervous about the idea because it is totally the opposite of my previous ideas about working. I think it goes back to my mother, who always refused to go to the company party or picnic because she thought any slight mis-step (the wrong shoes, bringing the wrong pot luck dish) would be worse than not going. Her attitude was always that no impression was probably the best impression. That’s even what she told me about this event when I mentioned it. I don’t entirely agree with her, but when something’s so ingrained in you, it’s hard to change.