small: Her body is small or thin young: her age is young so when you talk about age say صغيرة في العمر او السن and when you talk about body build sayبنيتها صغيرة

You could say also : عمرها صغير Literal Meaning : Her age is small.

my question was. This two sentence can be mean bothv. Am i correct ? ﻫﻲ صغيرة