It is really different for every bride.
Some brides on here are planning 2 years in advance, I however got engaged in February and my wedding is on the third november so only 8.5 months from engaged to married but i had everything booked within 3 months ( i went overseas for 3 months)
It depends when you want to get married? do you want it now or can you wait?
what kind of wedding do you want? small or elaborate?
Do you have the finances now or do you need to save? how long will it take you to save?
answer these questions then you can set a date and start planning
I am in a similiar situation.. We got engaged on Boxing day last year and are getting married on our six month anniversary in October. When my FH intially suggested this idea, I was like, "You can't plan a wedding in ten months!". But luckily, because we are getting married on a Thursday, we had no trouble booking anything. I did a lot of research on photographers and after speaking to a couple of self obssessed idiots, I went with a great photographer who is new to Oz. Other than that, I relied on my reception's recommendations. I feel that somehow I was kinda being somehow lured into advice that I didnt need, but I found the perfect celebrant and florist and it certainly takes out the stress of worrying about the intregity of these people. The stressful part for me, was planning the whole thing from overseas. You cant meet people face to face etc, plus FH has been away wayyyyyyyy too much for business this whole year and I have literally done everythig myself! I spent a whirlwind three weeks back in Oz meeting and organising everything, including my dress! In terms of the dress, it really depends on what you are after.. I found the most wonderful dress designer based in Brisbane of whom I had the pleasure of meeting with in Melbourne. She helped me try on some dresses and after getting an idea of what I was after, put two dresses together and made my perfect dress.. in two months! (well at least I hope so, my fittings arent until I arrive in Oz on the 4th October). I am only just now feeling calm about it all.. In all honestly, I never ever want to plan anything like this ever again. It has totally consumed my life!
On the other hand, one of my friends got engaged last month and from then to the actual wedding will be a total of eight weeks! Like others have said, its really about what you want or the way that you have dreamed your ideal wedding to be, before any timelines can be decided. The day after I got engaged, my sister and I checked out her favourite wedding reception (which is actually the reception we chose in the end, and booked it without FH seeing it!) and all of the weekends for the follwing Oct, Nov and Dec were already booked.
Good luck and congrats!