What age can a cat eat wet food?

There are some wet foods for kittens/cats/senior cats. Any age pretty much. Except for young kittens who aren't weaned yet, although wet food is easier for them to eat while being weaned. Look for cat foods that have a very high, named meat content (labelled as Chicken, Turkey, Rabbit, Lamb, Tuna, etc.) as the FIRST ingredient with no grains, wheat, corn or any other cereals. Be sure to keep away from Ingredients such as grain, corn, wheat gluten, various sugars as they serve no nutritional value to the cat whatsoever.

Kittens and cats are strict carnivores. They get all their nutritional needs from meat. Kittens in particular, need a lot of Protein and Fat in order to grow and develop in a healthy manner. Kittens need twice as much Protein as an adult cat does, so don't be surprised if you are feeding your kitten much more than you would an adult cat. Also, kittens have small stomachs, so the best method of feeding is "little and often", as often as four to six times a day for very young kittens.