I've not seen the Secret Life of AM Teen so not sure what she's like there, physically or otherwise.
For UA they hid her breasts, if they are big, very well and her face is young looking. Knowing now that she's 19 I wouldn't have guessed it. Age 14 would be my highest guess.
Reviewers were never going to like this movie Fish so any trashing by them on any point, including India's, is hyperbole as far as I see it.
Knowing she is 19 means that likely a sequel with her and Kate seeking out Michael will only give her more screen time. Plus if they advance the story and jump ahead a few years she could be 20/21 yr old actress playing 16/17. Mom and daughter fighting in latex! Now that is butts in seats for you, cha-ching!!