Terri has good advice, I agree completely with her suggestions. It is most important to establish a budget from the beginning. This is a one day event and you don't want to take out a loan or "borrow" from your retirement money to fund it. There are all kinds of weddings and they don't have to cost $20,000 to be lovely.
Regardless, congratulations!
p.s.---My DH didn't like our "philosophy" about spending on her wedding so she and her new hubby paid for a lot of it (used plastic, I might add). I think they're still paying for the wedding.........(got married on Catalina Island....)