generally a bom is a year or longer commitment- the shop keeps your card # and charges it with each shippment= if you decide to (drop out- they are entitled to charge your card for the remainder of the program-
you can probably contact the shop and ask for the completion of the program all at once- some times all of the kits for the year are all made up at the beginning- those shops have no problem letting you take it all at once- others cut the kits monthly- making it a bit more complicated.
bom's generally are an expensive way to go- and waiting a whole month for a block makes it easy to loose interest- i know some people who sign up- and just collect all of the kits- they do not even really look at them until they have everything and can just make their quilt---the danger with this is...if one month a mistake was made in your kit- it might be too late for a fix-
some shops send the boms out the same day every month- some send them out every other month- some the date varies- you just never know- usually all of that is explained when you sign up- if you choose to do another one you might want to work with a shop that has a definite monthly shipping/billing date.