In a sense, humanity is like a teenager getting ready to leave home for the first time. First Contact would force human civilization to grow up quickly. We would expand our perspective and perhaps face some unpleasant truths about the universe. It’s unlikely to be all good news coming from extraterrestrials. Judging from our own world, the wider universe is likely to be volatile and complicated. Entering into that wider universe will be exciting, challenging, and probably scary, all at the same time.
Will we cherish remembrances of our days of ignorance? Will we long for the times when our major concerns were terrorism and economic turmoil? It sounds crazy in our current perspective, but First Contact could bring challenges much, much greater than these and may exasperate the aforementioned problems greatly. I hate to say it, but First Contact could make things much worse in the short-term for humanity. If we can get through the initial unrest and emerge on a firm path, with a clear direction and steady hands, hopefully the situation will improve and allow us to enter into a new era in human history as jaded and experienced young adults and no longer naïve teenagers.