What's your own hair like? You can dye yours dark brown (can't tell for sure if it's chocolate or more neutral) to match her color, but pattern... If you have the same curl type (and texture) as she does then it's just a matter of finding a stylist who can give you the same cut, and then I'm sure there's styling and products she uses, and who knows what they are... I doubt her hair is just left alone when she is working, it looks styled to me, maybe hot rollers/curling iron... I know she is naturally curly but they maybe trying to achieve a more uniform look or bigger curl or something. I'm pretty sure something is done to give her the kind of lift at the root she has.
My hair is 3b and It looks like she changes her hair color between dark brown to auburn. My hair is naturally black and always stays above bsl. I guess it's too good to be true her hair looks nice because it's not natural.
Hers seems to me to be more 3a, but I might be wrong... Nicole Kidman looked like 3b in the very beginning of her career, but then later on started looking like 3a, because of what was done to her hair. Best bet is probably to take Sofia's pics to a good stylist who is a curl (and color) expert and talk to them about it. Maybe they could help you get if not exact same look then something close.