There's no reasonable way to estimate age within just a few months based on size. Growth depends partly on heredity and partly on husbandry. Some animals grow rapidly when they're babies and others don't, even when fed the same diet and kept in the same conditions. Corns generally all reach adult size with normal care and feeding at about 3 years.
You'd asked about traits like strawberry, dilute, or coral. While it's possible that your baby is carrying those genes, the only way you can tell for certain is with eventual breeding trials. It doesn't appear to be homo for dilute, but the others can be difficult to distinguish in a hatchling. Unless one knows the baby's parentage, assume it isn't carrying genes one cannot visually see until proven otherwise through breeding. As a pet-shop pick-up she's probably a typical snow.
Whatever type of snow she is, you're going to enjoy watching her grow. I've been surprisingly charmed by the subtle beauty of snows and they way it develops.
