Do chubby kids( girls) turn inot chubby adults?

It depends
My cousin was a cubby child and now she is a very overweight teenager
my bffs sister was a cubby child and now she is very slim

Not necessarily. I was a chubby kid because I had crap for food when I lived with my mother. I moved in with my father when I was 14 years old and had access to fresh produce and home cooked meals instead of fried, fatty, microwaved junk and went from a size 14 to a size 3. Without a change in diet or activity level, I'm not sure if a kid could lose the weight.

No it really depends on the child...
I was skinny most my life.. i gained it in high school and am now fixing it

I was a skinny kid, slightly overweight at a pre-teen (due to medications), average as a teen, and overweight as an adult. It all depends.

As other have said it just depends on lifestyle, diet, genetics, and medications. I've seen slim kids become grossly overweight and I've seen overweight chumby kids become healthy adults. I've seen chubby kids stay overweight all through out childhood and adulthood. I've also have seen families were everyone but mom is a bean pole or everyone but one child is a bean pole.

Not necessarily genetics works in here...

Childhood is the time to teach healthy eating habits and lifestyle.

not always

Not always. Of course diet and excercize, as in not eating a lot of snack type foods and not spending hours and hours in front of the t.v. or a video game, plays an important role but there are kids who are a bit chubby at age ten (a girls body is definitly going thru some changes around that time) but then hit a growth spurt and in gaining height they lose the chubbyness.