Disclaimer: I am an old fart.
You haven't posted (in this thread) you height and weight. There were times in my teens when I thought I was a cow. Looking at those photos 10, 20, 40 years later, I can see that I wasn't a twig, but I certainly was pretty and healthy looking. There were times when I thought I was chubby. Looking at those photos years later, I realize that "chubby" for me as a teenager meant that I didn't look like the skinniest girl in school.
IOW, one of the best lessons you can learn is to not compare yourself to others. Are you really chubby? If so, cut out a few snacks and stay active. Eat well always. If you're only chubby when compared to TwigFigure Tammy, don't worry about it - chances are you're going to have bodacious ta-tas, while she stays relatively flat chested.
"Right is right, even if no one is doing it; wrong is wrong, even if everyone is doing it." - St. Augustine