Hi Sarah - welcome! Sounds like you're approaching a place similar to where I found myself last summer awaiting my first opportunity to meet Neil after 15 years. It's great that you're generating some discussion here to move that nervous and expectant energy!
I echo what all the others on this thread have said, but I'll add my unique experience of meeting Neil.
First of all let me say that in the time since I did meet him I've realized that I had a great deal of expectation riding on that moment which I was oblivious to at the time. My "inner little girl" was out everywhere - I even wore my hair up in pigtails... My life was complete chaos at the time of his concert, and I was really needing some kind of affirmation and had apparently subconsciously decided I would find it in meeting him. (It's all very interesting to me now... though it was a crazy rollercoaster at the time!)
Anyway, I went through all of these crazy contortions, which began with a search to find someone to accompany me to the concert. As none of my friends are fans, I ended up running a contest online to give my extra ticket to a deserving fan. In that process, I created a small book of all the contestant's responses to my many Neil questions. I selected a winner (the person with the most intriguing answers) and met her in the line. I brought a copy of the book to the show to offer Neil as proof of my devotion or fandom or... something...
Before the show I spotted Neil walking out to the bus from the theatre and made my way over to him. He was shoving a heavy suitcase under the bus, so I stood a ways back waiting for a good moment to catch his attention. A group of rather aggressive fans had amassed behind me and before I knew it one of them shouted out, "Hey Neil, nice sweater!" He looked over his shoulder (at me!)

with an expression that seemed to say, "Do I not look BUSY to you right now??" Needless to say, I was very embarassed. (I'm kinda shy and that's just not the kind of comment I'd yell out at a moment like that.)
Suitcase sucessfully stowed, he then began to walk by me back toward the stage door and I realized I had to sieze the moment, red cardigan sweater, and all. I shoved the book into his hands, saying something like "Here, I made this for you." He looked at the book and then back at me, all with the same annoyed expression on his face. Then he said, "I don't think I can read this now," but he accepted it. I think I sorta smiled and then him walk into the swarm of fans behind me who demanded he sign stacks of cd booklets and take pictures for about 10 minutes.
Needless to say I was a bit nonplussed at my firstever experience of meeting Neil. I knew it was pre-show and he obviously had a lot going on. Plus he didn't appear to be in any sort of good mood in general. Even though I had a slew of reasons to know it was just a bad time to catch him, I still felt pretty bummed out and had a hard time not taking his lack of enthusiasm for this wonderful gift full of all my unconscious expectations personally (
After hours on the sidewalk, the show began

, and the opening act was finally done. Neil came out and was just AMAZING. I had heard it from all of you that the show would be incredible, and it really was! Hearing music that I've listened to and loved for half of my life performed live - by Neil... nothing like it!!
Then, halfway through the show, just as I was shaking off my earlier melancholy, he mentioned my contest! He mentioned it in reference to DDIO, wondering if it was the winner's favorite song. (It was!) That was huge energy rush, let me tell you. Wow. Made my earlier confusion and contortions worth it, boy! From then out I had a great time, no more demons bugging me about things not going *right*. (What is *right* anyway, in the vortex of life?)
After the show I did as mentioned above by many others, waiting by the bus with my newly found Neil friends. We waited maybe 45 minutes to an hour before he emerged. I stood next to him for a while in the midst of the swarm, while others got their posters and cd's signed. I really liked just standing next to him. It felt really cool. It was funny that he was only a little taller than me, and his hair was so grey. I think I stepped on his foot a couple of times, with the jostling of the crowd. I waited till some of the fervor had died down and asked if he'd sign a copy of my book for me. I told him I was really glad to hear he'd had a chance to look at it after all, and he said yes, he'd found it to be "interesting"
So I say, Sarah go for it - hang out and meet him afterwards (I advocate after instead of before). Don't hold back! He's is quite gracious and you really can't mess it up - I feel like living proof of that!
Have a wonderful time at the show! And thanks for reading my long tale.
~ Colleen