33girl is totally right. I planned our 5 year this spring (oh my gosh was that difficult!) and it was an amazing event. Yes it was only 5 years, but we brought our alumnae back, most for the first time since they graduated and they had a wonderful time. People with drama really did put it away, and the stuff that could be put away, was at least muted because there were so many people. Out of 35 alumnae 25 came back, one even from Japan. You will also get to meet the actives, and alumnae you didn't know. The tough part about a young chapter, I'm talking about the women from founders to about 5-6 years after installation, is that there is still so much to do. A chapter is not created in a short period of time, and people hold on to certain items/traditions that may not end up working (and we had lots) then you get the resentment for changing, but all in all, the reunion brought it all together and let everyone see what they created or are a part of. It was amazing and I think that you should really just do it. If it is too horrible, leave early, say you had an emergency, but you'll never know till you go.
sorry for meandering thoughts