There is no single "best" girl shape size. Beauty and attractiveness are subjective and culturally influenced, and they are not solely determined by physical measurements.
While certain proportions, such as the 36-24-36 hourglass figure, have been historically popularized as ideal, this is a narrow and unrealistic standard for most women. Individual attractiveness is influenced by various factors beyond measurements, including personality, confidence, health, style, and cultural context.
The emphasis on specific body shapes can contribute to body image issues and unrealistic expectations. A healthy and confident individual is generally considered more attractive than someone who conforms to a specific size or shape but lacks self-assurance.
Ultimately, the "best" girl shape size is the one in which a person feels healthy, comfortable, and confident.