How old is she?

I'm being overly paranoid....but I wonder if I'm feeding Jade on the "right schedule". I was told she was 2-3 weeks. Her eyes are open. She can hear as she responds to noise, she is playing. She moved into the sun rather than the shade in her "house". She can purr & she is vocal.

How would I know how old she is? I need a weight on her, but all I've got is my bathroom scale. I'm taking her to the shelter tomorrow night to get a weight.

if shes hearing and playing about i would say 3-4 weeks maybe??