In reading your question, several red flags pop up. First a 12 mm overbite is quite significant. I can understand the desire to get it fixed for your upcoming wedding. But that is a lot to do in a short time...especially with Invisalign. I'm not discounting Invisalign...it's great at closing spaces. But in your situation it may not be ideal. Depending on the cause of the overbite (tons of space versus a small lower jaw), fixed appliances, which may be less expensive, might give you a better result. And by using fixed, you take out the 4-6 week lab time needed for aligners. As far as a discount goes...many orthodontists give courtesy discounts for clergy. Are you still a missionary? But be aware, due to the substantial lab fee doctors must pay for the aligners, it might be hard to discount much. So again, consider some cosmetic fixed appliances. And be sure to visit a certified SPECIALIST orthontist. Good luck.