We moved in together after less than a month of being a couple (although he was practically living with me during that time anyway, we never wanted to be apart), then we got married five months after we moved in together. We'd been together six months lol Our third wedding anniversary is early next year.
And on the other hand, I know couples who were together for x amount of months/years before moving in together, lived together for x amount of months/years before getting engaged, were engaged for x amount of months/years before getting married, in order to determine whether they would make it last before making the official commitment... and then ended up divorced before their first wedding anniversary. So I don't think the success of a relationship has anything to do with the amount of time involved - for some couples, time will strengthen their bond, for others, it will wear away at the relationship and turn the cracks into shatters.