My oldest pair is now 4 years old and they are totally the same in size. We had one 9 years old female and she was a lot bigger than them, but she also had 6 years of growing more. I never really saw big differences in size gender-wise, some individuals are just bigger but it can happen to both males and females.
As for behaviour, I'm not sure if it's a rule but our males were all calmer than females, no matter the ageFemales tended to be more food driven or shy while the males were all an easy-going dudes. But that's just our experiences, I don't really know if it's something typical in this species or just our luck.