This linguistic confusion is why Americans call the Pennsylvania Dutch Dutch even though they're Germans. To review: this country is the Netherlands, its people are Dutch, they speak Dutch. There is no country called Holland, but there are provinces of North and South Holland.
In clean, uncrowded conditions in tanks or ponds, goldfish grow fast. They can grow to a few inches (1 to 4 inches) within the first year. It really depends on their genetics and living situation. It may take a year or two before they change color from brown to gold or whatever color their parents were.
Your goldfish eggs should be kept in water that is not deeper than 6 inches. In deeper water the pressure can damage the fry and make it hard for them to reach the surface. After rinsing the eggs place them in a 20 gallon tank. You should raise the temperature to about 700F. The fish will hatch in 3-4 days.