Hey there. I'm shooting a wedding reception tomorrow.any advice?

I'm 10 months experienced. I will be using a Nikon 5100. I'm used to and very very comfortable with that camera. (In fact so much I bought that camera I bought it as my first Dslr.)

The lady-my former teacher- that hired me wants me to get the important Moments -first dance, etc- and I'm nervous.

Any advice? I'm assuming it will be darkish /dance club mood. Flash? The camera only has one lens: a 18mm to 55mm.

My experience is mostly photojournalistic. I'm 18 and this is a paid job with food benefits.

Added (1). Haha sorry sorry I should of mentiones she hired a pro photographer. I'm just doing it for the experience. So she can take my work or leave it. Whatever.

The fact that you're asking for advice the day before the event tells me you're not ready for this. This takes weeks to plan ahead. Indoors, no flash, and a very slow kit lens? Your clint is going to be one very unhappy camper.
You have a right to be nervous. A wedding is one of the hardest things to shoot. And you haven't preplanned anything?
Sorry to be so negative, but you should have known better.

Get a few wide shots of the event

But mainly faces of guests and family enjoying each other

Plus, huge tip…

Shoot people at their eye level, move the lens up or down to their eye level.
And get close! Do not be shy, get close for many shots.

Have fun. Keep an eye on the pro and take notes.

If you don't know what to do, and you don't have time to learn proper techniques, or that you don't have a flash (or don't know what to do with it even if you do have one), two words: AUTO MODE.