Your daughter’s quinceañera can be very important to her, but one thing to keep in mind is that your dog will not be generally aware of his quince. Dogs do not seem to share our understanding of the concept of time. It is impossible for your dog to comprehend that he is 15 years old, much less the cultural significance of this milestone in a young woman’s life. This situational aloofness takes a lot of pressure out of the process of planning your dog’s quince.
Minimal planning is required for your dog’s quince. There is no need to coordinate with your church, since dogs don’t have free will or human souls, and aren’t obligated (are in fact discouraged) to attend mass, ever. You may attend mass on your own that day, but the important thing is to make sure that you do not bring your dog to church for his quince, as that is disrespectful and probably in most cases sacrilegious.
Create a guest list. Some people might be critical of the idea that you are dressing your dog up and having a party for him. Who cares about those people; they are no fun at parties anyway. However, possibly avoid inviting professional contacts or others with whom you need to preserve a certain reputation. Consider whether a person might conclude that California has changed you, and that such a party is just another indication that society is on the brink of total collapse, were they to receive an invitation to your dog quince.
Consider your catering options. Be respectful of your dog’s guests, and provide food that they will enjoy. If some of it falls on the floor, your dog will probably enjoy it as well, but keep in mind that he is 15, and if he eats a bunch of human food in one day, there can be consequences ranging from gross to tragic.
The most important part is to enjoy the day. This whole “dog quince” idea is really one big excuse to have people over. Even so, please be considerate of your 15 year old dog and take him on his usual walks that day, so that everybody has a great time, including the guest of honor.