Cockatiels are usually considered "babies" until they hit sexual maturity, which is around six months of age. I would say it is a safe bet to say it is adult at a year, because I don’t personally know your bird or know when it goes through her hormonal changes.

At around that age. It is good to offer them at a young age. Keeps them healthy, makes them live longer, and I have found that my bird like to eat fruits and vegetables and have a varied diet.

They can eat certain meats that are well cooked, and they can have hard boiled, scrambled, and crushed eggs/eggshells. Give them a cuddle bone, mineral blocks, supplemented diet, pasta.

Greens: Kale, Bok choy, spinach, chard, mustard greens, radish, carrot tops, beet tops, dandelion greens (make sure they haven’t been sprayed or collected near a roadway) and just about any other leafy green veggie.

Veggies: Carrots, peas, zucchini, corn, squash, radishes, bell pepper, broccoli, green beans, Brussels sprouts, cauliflower, sweet potatoes, chili peppers, beets, legumes, frozen mixed veggies, kale, asparagus, bean/alfalfa sprouts, spinach.

Grains: Steamed rice (white, brown, wild) cooked pasta, whole wheat and multi-grain bread, popcorn (no butter), bran muffins, polenta, grits, cous cous, sprouted seeds and grains (quinoa, amaranth, millet, teff, kamut, spelt), oatmeal, all natural cereal.

Proteins: Raw sunflower seed (small amounts), chicken, eggs, fish, small amounts of hard cheese such as Jack and cheddar, tofu, cooked beans (lentil, kidney, black, garbanzo, navy, white).

Fruit: Apples (seeds removed), peaches, bananas, melons, mango, pomegranate, oranges, papaya, strawberries, plums, pears, berries, nectarines, cherries, kiwis, grapes.(Please remove all pits from fruit.)

Poisonous: Chocolate, avocado, sugary foods, salty foods, greasy foods, food high in fat, caffeine, soda, alcohol, pits/seeds/cores of fruits/vegetables, candy, rhubarb.