Sadly, there is no actual answer to this question. I'm sorry to say this, but most Sonic ファン are called as such for a reason anyone can tell. Because of this, no one has ever really paid much attention to this question, so no one has made much of an effort to answer this question. There are probably a couple of ファン fictions out there that try to answer this question, but those can't be considered an actual fact of continuity. Of course, SEGA has taken a piss on continuity, but that's beside the point.
The earliest recorded existence of Cream and Cheese together is in their first appearance, which was in Sonic Advance II. This gives the impression that Cheese may have been an earliy addition to Cheese's family while she was much younger, possibly 6 または 5. The reason why she couldn't possibly have met Cheese at birth is because Chaos wouldn't have allowed a chao to be loyal to... a baby. It's logical, but not impossible.
But again, this can be put up for speculation. This isn't necessarily the truth considering how little proof there is.