Bitter-sweet Sixteen (Coming of Age)

When a Magical Girl reaches her sixteenth birthday it is both a joyous and somber occasion, for it is this day that the Magical Girl retires from active duty in the Magic Defense League. When the bell tolls the exact moment of her sixteenth year the powers bestowed by the Dream Mother leave her permanently, leaving her with only the experience and memories of her time in the Corp.
Insofar as Twilight City is concerned, any retired Magical Girl is considered of age in the legal sense. She is free to partake of age-restricted items such as alcohol, though this also means that she can be prosecuted in similar fashion should she face criminal charges for any reason. Depending on services rendered as an acting Magical Girl, she may even be given the opportunity to continue working with the Magic Defense League as a civilian.

Execution

While the celebration and festivities varies from person to person, much as a normal birthday does, there are a few things that are considered must-have standards for the coming of age ceremony.
Food, of course, is a given, though the extent to which family and friends prepare is extravagant to say the least. A veritable feast is offered to the celebrants, and it is one of the few times the people of Twilight City allow themselves to so eat so wantonly. In addition to decadent food, drink is also provided (including alcohol for the adults and the newly-of-age birthday girl.)
Presents are common, and usually carry a more personal meaning than some trinket or bauble. It is not uncommon to have a gift-giving segment of the celebration, wherein each guest presents their gift personally and one at a time. It is then opened in front of the other guests, often with an explanation towards its symbolic significance for the other guests. It is equal parts thanking the retiree, as well as honoring her through remembrance of her deeds in the line of duty.
Another practice is the Bestowing of the Mantle. Usually held at the start of the celebration, this practice is one of somber gravitas. Under the supervision of a MDL representative, usually a team liaison or coordinator, this is the official passing on of responsibilities; albeit to one who is already saddle with these duties. The retiree symbolically places upon the shoulders of an active duty member (often a friend or team mate whom she worked with) a light cloak. These cloaks are highly personalized, and express the personalities of both the retiree and the recipient.