First day on the slopes

If you have ski goggles, you don't need sunglasses (except for driving, so keep sunglasses in the car).  As for hydration, I'd bring a small bottle of water or gatorade and keep it in my pocket.  Yeah, it might bulge out, but it doesn't bother me.    Keep more bottles in your car so that you can refill.  I bet you won't park too far from the slope, especially when you go on a weekday.

Depends on the weather, I'd have a base layer of wicking t-shirt, a fleece/sweat shirt, a waterproof shell.  If cold, add another layer under the shell.  A fleece/wool hat (or head band if not too cold) would be good to cover the ears.  Use the long underpants only if you have a waterproof shell pants without insulation. 

When I was a poor college student learning skiing, I only took some water and PBJ sandwich plus some crackers to the slope, skied from mountain opens till it closes, taking a few breaks in between.   Did know anything about energy bars or anything technical.  But we had fun.  So don't stress out about what to bring.  I'm sure you'll have fun too.