How far in advance should I ask someone to prom?

How far in advance should I ask someone to prom?

Pamela Pekerman (Trend Spotter, Bagista) gives expert video advice on: Who's a better prom date, a friend or a boyfriend or girlfriend?; How far in advance should I ask someone to prom?; Is it OK for a girl to ask a boy to prom? and more...

If, obviously you're not dating somebody and you want to ask someone new, you kind of want to give the person a month or two in advance notice before you ask them to the prom because they need time to prepare and you want to give them that courtesy.