Maybe she liked her voice more, but she worded it bad.
It's like Gaga saying her voice was better when she smoked, when both of them have imrpoved so much.
It's just that her voice was different back then, and it's not only cuz of the smoking, 4 years from 21 to 25 year old is a lot of time and her voice has changed.
Maybe she liked her voice better then, but it's stronger now.