Aqua Is Not Norted
Aqua did NOT become Norted
She had simply fallen to the Darkness
In Kingdom Hearts 2.8, Aqua mentions that the longer she stayed in the Realm of Darkness, the more lost she felt she was becoming
This is a clear answer to what we see in the KH3 E3 trailer and why she had silver hair and golden eyes
The same thing happened to Ansem The Wise, if you recall. The longer he spent in the Realm of Darkness, the more he felt himself falling to the darkness