To be honest, you're not going to ruin it if you take a peek. There's a blanket of CO2 covering the beer which should keep out oxygen but it won't keep everything out however it'll do for a quick peek. It might even calm you down a bit. It took me about three batches to stop wanting to peek. Now a month without opening it is a walk in the park.
I remember my first batch. Just over a year ago, and I remember peeking and having such fear that I ruined everything. It was such a no-no thing to do. I finally confessed to the friend who got me into brewing and he laughed. Told me eventually I'd stop wanting to peek but it probably didn't ruin the beer.
Now if you REALLY want to see what's going on, use a glass carboy. It you only have a 5-gallon, do a 2.5 gallon batch. Heck, it does't even have to be good. Just some LME and hops boiled together, and whatever yeast you want to throw in there. Be cheap about it. Once it gets going you'll be mesmorized. If you don't have a 5-gallon carboy, go get a one gallon one. They're only a few bucks and you can make an even smaller "watch-me" beer.
