It's your Quince plan for it!      
Here's an unofficial guide to planning for your Quince!  Of course things don't always go as planned but here's a guide to keep you going on the direct path to a perfect day!

12 Months Prior
Select a date 
Set a budget 
Pick your padrinos 
Start your guest list 
Research magazines for dress and theme ideas 
Start looking for a photographer, music, food and party locations.
Talk with your church and determine their requirements
Choose your theme, style and colors
Choose potential attendants

11 Months Prior 
Choose the food for your event
Visit locations
Invite/confirm attendants
Select and book a food vendor
Nows the time to book all those Quince resources you'll need:
DJ, Food, Church, Florist, Photographers, Limos etc.
Select and order invitations
Meet with attendants to select dresses

9 Months Prior
Send out announcements
Select and order your gown
Select and order attendant dresses
Buy decorations

6 Months Prior
Arrange rehearsal dinner
Select and order attendant tuxedos

3 Months Prior 
Make hair and make-up appointments 
Make final guest list 
Pick up invitations
Address invitations

2 Months Prior 
Send out invitations
Start RSVP list
Select/purchase attendant gifts
Make song lists and line up you want the DJ to follow

1 Month Prior 
Start writing thank-yous
Final fitting for gown
Final fittings for attendant gowns
Pick up programs
Get fitting for tuxedos

3 Weeks Prior
Pick-up gown
Contact guests who haven't responded
Update RSVP list
Confirm tuxedo pick-up
Pick-up attendants gowns

1 Week Prior
Create seating chart
Confirm counts for food/drink vendors
Final attendant meeting
Prepare attendant gifts

1 Day Prior
Rehearsal and rehearsal dinner
Pick-up tuxedos

Quince Day 
Don't forget to eat, breathe and relax.
Hair and make-up appointment

Once your Quince is over don't forget to return all Tuxedos etc.  Most importantly send out those Thank You cards to all those who came and shared your day.