Depends how tall she is. She's obviously a sturdy lady - if she was 5'10" or more she could be a 16. But, perspective of the surroundings in her photos suggests that she's relatively short, 5'2" maybe? At that height she looks 12/14. Obviously not an 8 though!
To be honest, her photos show her figure off reasonably well don't they? I'd rather see photos like that and make my own judgement based on them cos clothing sizes are pretty variable and subject to fit/cut too.
I've got clothes ranging from M to XL that fit me fine. Also if I say I'm an "L" it gives you no indication of my physique/body whatsoever does it.... I could be ripped/muscular or dad bod or chubby or a tall wiry whippet. I reckon saying "12" or whatever is equally vague and meaningless.