This isn't uncommon--- give it time--- keep doing the stuff you did to build trust early on (and if you didn't ever have to build trust back then because your bird was young, you may have to do that now). It is like a teen who finally decides they need to evaluate their parents after all of those years lol.
Just make sure you keep any petting to the head and neck and keep your bird away from dark spaces. If he/she is hitting puberty, any shadowy spaces or cuddling can increase the hormonal impact and lead to territorial stuff, aggression, screaming etc.
Pretty sure it's breeding season for some varieties of cockatoos! Mine just bit me for the first time in a year and was very restless all day (about 2 months every year she gets really weird). All birds have a rocky patch once a year-ish (usually anyway) but puberty is different in that it can last longer and often requires changes on behalf of the "parront".