Today's party-organizers would prefer a themed party so everything will be in harmony, from the choice of the venue, invitation, cake, backdrop, costumes, give-aways, program, and the likes. When anticipating to celebrate your child's or mom's nth birthday, it is advisable to plan out at least two months away from the scheduled celebration. Give time for the printing of the invitation and its distribution. Ideally, invitations should be sent at least a week before the occasion. Less than that might find invited people refusing because of appointments and other schedules. If you can circulate the invitations two weeks earlier so much the better, but don't forget to remind them by phone a day or two before.