I think there is nothing wrong with either date! Do you have a preference for fall v. spring - as far as preferred colors, weather (do you want anything outdoors), etc.?
Personally, for me a longer engagement (2 years) worked better. We had bought a house only about a month before we got engaged, plus I was studying for a professional exam the following fall (which got pushed back to spring), plus we had some family/personal issues to deal with... so I wasn't even able to start on the planning until we were about 10 months out. And now with 5 months to go, it's pretty much all done
It sounds like $$ is probably the biggest issue for you guys, so why don't you sit down and figure out how much you can afford now, and what you can get for that money... and if you don't think it's enough, then maybe you should wait. (Or go the opposite way, figure out how much you'd like to spend to throw the shindig of your dreams, and then determine how long it would take you to save up that much).