We were planning to wait until January (note: long distance relationship for 18 months, I moved to Oregon in June) - but I was getting impatient!!! His parents decided they needed one more mission trip to India - his dad was marrying us - so, one day he comes to my apartment and says "how 'bout October 13?" (another note: he hadn't even formally proposed yet) - I said "for what?" ........... he said "to get married" - I said "okay". We had 5 weeks to put together the affair. It was very casual - but there is still tons to do!
bottom line........... picking the date is almost always based on 50 outside forces causing you to pick the date that works best for everyone involved. Its not the date that matters anyway......... get married when its convenient - celebrate your anniversary whenever the heck you want!