Is this crazy to even consider? Asked to shoot a wedding.

Coworker today asked if I'd shoot his kids wedding. I am not a professional. I am a fairly enthusiastic amateur who has an eye for composition and knows enough to get the results I want. But I'm not a pro.

That being said, it was made clear that the bulk wanted is the Ceremony itself, most of the candid reception stuff would be from disposables but I'd be doing some shooting there too obviously. I have a decent camera and glass (D500, 16-80 f2.8-4, 70-200 f2.8, 35mm f1.8 among other not as fast stuff), what I don't have is a flash of any kind currently. A speed light would be a quick pickup, but I'm not sure if I want to get into remote lighting, umbrellas, etc. I'm not looking to become a pro either.

With clear expectations set about what both sides expect ....... Is this a bad idea or worth exploring as an opportunity? I'm on the fence but leaning towards doing it with both sides having clear understandings.

Edit - Really good advice from everyone. I will add that I was informed by him that his kid said they'd take the raw files and edit themselves even (which I'm fine with). However, some great points are being made and though I'm confident in my ability to make it work, there's too many risks of *something going bad. I'm most likely going to decline. Thank you all.