A good lens for wedding, Nikon user here

So for a few months I have been sucked into really getting into my photography. I did have the option of going to school for it, but I could not afford it and make the move. So I decided to learn on my own. I have recently just been doing portrait photos and such like that with my 35mm 1.8 and 50mm 1.8. But I was recently asked to do a wedding. What I'm wondering is if I actually have the right equipment for this. The lens mentioned above are the only ones I have. I know the Nikon 17-55 f2.8 is know for being good for weddings, but $800 dollars for a used one… O_O so I'm wondering, what is another good one that can be used. Obviously a zoom lens, but my budget would have to be around $300. I only have a Nikon D5000 and decided on that camera to start me out, I know it's not an excellent body, but it's all I have at the moment and make do with it. I actually turned the girl down, telling her that I did not feel as if I would have everything I need to do her photo's and that I would rather her be very happy with someone that had the things they need to do the photos. She was a friends so I just told out right why. I have been staying away from wedding offers because I feel like I do not want to take on the weight of responsibility with someone's biggest day equipped with only those lens.Am I making a mistake?

I wouldn't shoot a wedding at gunpoint. Or babies. I've done a few portraits, but friends and family. I *loathe* shooting people, because they get all fake & stuff when they see a camera pointed at them. A zoom would be a necessity for a wedding, though… Those two fixed lenses you have limit you in where you'd have to stand. Also, an off-camera flash would definitely help. BTW, it's not the camera that makes the image blah blah blah… If you can't get a decent shot with what you got, a $30K Hassalblad won't help. And boy… Wedding shots… Screw up and you'll have the wrath of Bridezilla (and her mother) on you.

Using the D5000, the AF-S 50 mm f/1.4 and 24-70 mm f/2.8 are the two most used by the wedding photographers I know

Everyone wants to spend very little money on their equipment, but if you bill enough for your services, you will soon have exactly the equipment you really need

Here is a link that can help you figure out what you have to bill to stay in business

https://www.nppa.org/professional_development/business_practices/cdb/cdbcalc.cfm

If you behave properly in church, the priest or pastor will allow you to get near especially if they love dSLRs too. Use the 50mm for the ceremony. Don't hesitate on using the flash. It is better to be sure than sorry. For groupies, switch to the 35mm. If the group gets big, curve the line at both ends. You may need to buy a bigger flash gun. Your camera is perfectly all right. You can do anything with it.

I started photography doing weddings with those two lenses only and a generic external flash. It was the film era so basically I had wide and normal. I was even closer to the action than where you will be.