1. God made the universe older that its existence so it could support life. Fruit trees, for example, had to be fully-mature, else there would be nothing for Adam and Eve to eat. In addition, Adam and Even themselves had to be old enough to get married, have children, communicate with God, name the animals, and work as a husbandman in the Garden. Stars in the sky had to be spaced just right - (God didn't just put them out there randomly); the soil had to have the proper pH balance, the sun just the right age, etc.
2. The world looks old because it is old. It wasn't just meant to look old --- it is old. The world is not "much younger", as you seem to think I'm saying.
3. Since the physical age of the earth does not contradict the Bible - (how can it, the Bible doesn't say how old the earth is), I see no contradiction at all. There are two ages --- one physical, one existential. The earth is 4.57 billion years old physically, and is 6100 years old existentially.