Confused About The Age Of My Budgie

[Ellabow 0]

Hi there, I bought a beautiful budgie a few days ago. I got her from a pet shop who claimed that their budgies were all 8-10 weeks old. I’d done some research into sexing before hand to see if I could get an idea of what gender I was purchasing however when I got there, the Ceres of the budgies seemed more “adult”. The budgie I chose had a dark brown cere, the lady said she was a girl based on her bite? I double checked the age and they said definitely 8-10 weeks. Given that I’m quite new to all this I took their word for it but since getting her home I’ve become more convinced she is older. It doesn’t bother me, she is lovely and I wouldn’t swap her but it would be nice to know, especially as I’ve read that taming older budgies can be more tricky. I’ll attach a picture below for opinions. It’s not been edited and it’s from the day I purchased her. Thanks 

[Ellabow 0]

A few more pics