Who usually pays for a wedding these days? The groom? The bride? Their families?

My girlfriend and I want to get married within the next three years. We were talking about weddings today and we were saying how all we want is for things to be small, simple, nice, and inexpensive. We basically only wants us, her parents, my parents, and a few other people there. We want to get married at a small church and go to dinner at this nice mexican restaurant (she's mexican) that her and her parents are friends with the owner afterwards. She says that all this is going to cost is $1500-$2000 for everything. Her dress, my tux, the cake, the church, the flowers, the food (since her dad said they could get the food for free or for very cheap since we know the owners), and such. The rings and honeymoon NOT included. She does want to spend a bit on those two things. ($3500 for her bridal set and $3500 for our honeymoon). She said she would pay for the entire wedding since I am buying her ring and the honeymoon. Is this right? I feel kind of guilty if she paid for the entire wedding but then again I could use the help because I'm in college and she is starting college next year and it really isn't a lot. Who pays for the wedding expenses?