Working at a university, I get these requests all the time, from coworkers whose kids are getting married, to students who are marrying after graduation. Weddings are a highly specialized field, and require experience and a certain kind of personality and temperament. Even as a long time professional photographer, I would feel very uncomfortable shooting a wedding, as it is not my specialty. So I provide these folks with my personal congratulations and a list of great local wedding photographers.
I would never say yes to this sort of request, and *certainly* never do this for money. Bad idea in so many ways, sorry.