I would bring a few books, you DS, and basically anything else you can think of to distract yourself and look busy to the other people there, so they'll be less likely to talk to you (assuming you don't want them to). If you have a tablet or a laptop, you could bring it, but since there will be kids there, be warned that they'll probably want to watch what you're doing and use it themselves, so you'll get more social attention. I tend to leave mine at home for that reason. Then you can sit and do something while everyone talks, and you'll probably only have to interact much while you eat and maybe when you first get there and before you leave. Also, if possible, ask whoever you're going with how long they plan to stay, so you can have a better idea of how many distractions you need to bring and so you can keep an eye on the time.
I know it's hard, but try not to worry about things that are out of your control, like the food and where you'll be sitting. You'll only stress yourself out because there's not much you can do about those things. If it helps, you can try to break down specific worries, like if you're worried they won't make anything you'll like, you can bring a few snacks to eat if needed. If you're worried you'll be sitting outside for a long time, you can bring some sunscreen. Things like that that might help you stop worrying so much.
Last edited by Quill on 12 Nov 2015, 7:05 pm, edited 2 times in total.