I Was There song meaning

This is the only released Green Day song that was written by their ex-drummer Al Sobrante (John Kiffmeyer). In this song the author talks about his memories and how he feels about the past. He regrets that it's all over, but doesn't let it bring him down, because there's always tomorrow. He's glad that he's experienced what he has, that he "was there", but he looks into the future because there's still a lot more life to live.