tevo said:
And in all honesty, I need the money.
So, convey to these folks that you need to be payed for your photographic services. You need to be payed a set fee for a pre-determined number of hours, or a certain "level of coverage". I would talk to your parents about this issue, just to see what they have to tell you about shooting photos of weddings for pay,and to get a 2nd and 3rd opinion from people whom you know personally.
You can DO THIS event. It's a backyard wedding!
It's all scheduled out....you know exactly what's gonna happen and in what order. It's a bunch of people playing dress-up, and knowing full well that they will be photographed.
This is presently my issue. I have been unable to get in contact with the groom, and have no idea what the itinerary of the wedding is / what the location looks like / what they are expecting. If I can't meet with them before Thursday then I will have to decline this engagement.
From what I have gathered, weddings go like this. Please fix any errors!
Ushers hand out programs to people showing up.
Guest seated.
Groom walks to alter.
Bridesmaids and groomsmen walk in
Grandparents, mother, siblings and are seated after
Flower girls and Ring bearer walk down the aisle.
Bride walks down the aisle, escorted by father
Father is seated in front row by mother.
Maid of honor takes bride's bouquet.
Priest speaks, vows are said, priest speaks.
The Kiss

Maid of honor hands bouquet to bride.
Bride and groom walk back down the aisle.
People get up and leave
Family sticks around for pictures.
All other guests head to reception.
Reception:
Bride and Groom are announced
First Dance
Father/daughter dance
Mother/Groom dance
Dinner
Cutting of the cake
Toast
Serve cake
Toss bouquet
Dance
Everyone gets drunk and then leaves
This is based off of a few google search results. I have no recollection of the one wedding I went to when I was 4, so I really have no first hand experience with weddings.