As the egg ages, the air cell in the large end becomes larger. As it does, the egg becomes more buoyant. An older egg will stand up in the bowl of water and really old egg bobs along the top. A cloudy white is a sign of freshness, not age. The cloudiness comes from the high carbon dioxide content of a freshly laid egg.
Thick white is a sign of freshness.
If there is a lot of jelly-like white, the egg is fresh. As it ages the white thins out. The stringy things on the sides of the yolk are the chalazae. These are twisted strands of white which act like nature's little seat belts holding the yolk securely and protected in the middle of the white. The more prominent the chalazae, the fresher the egg.