I can't have a dog or cat where I live, so I am thinking about getting a parakeet. They are a good introduction to bird ownership. Other more exotic and expensive birds can come later if you find you can handle the parakeet.
Parakeets sing, can be trained to do tricks and talk, and sometimes are affectionate.
The life span averages 5 to 10 years with proper care and good luck. As for the diet, an all seed diet is junk food for your bird. A wide variety of fruits and vegetables as well as commercially available pellet food, will give your bird the best nutrition. Budgies are psittacines, a classification of birds with hooked bills and two toes front and back. Your veterinarian, preferably one who feels comfortable with avian patients, would be a good source of information and could test for this disease.