I can see your excitement at the thought of getting a 'too but have you seen
All About Cockatoos - MyToos.com which really spells out what it is like to own one. You say you have reached the great age of 15 years old which IMO is too young. Cockatoos are expensive when they get sick, need toys on regular supply and a large expensive cage. Your social time would be severely cramped, you may not mind now but what happens when you want to go find love? Would you want to go to college or university? How would that work? Can see you are well intentioned but please be sensible and wait until your life has settled down and is more mapped out before going for a Cockatoo or a Macaw for that matter. Both are very long lived and demand a lot to be happy and healthy. A little patience will definitely pay off, believe me!