"My sister-in-law wears skirts."
Translation:Min svigerinne går i skjørt.
Certain dialects prefer one over the other. Having the possessive first was much more common in the Oslo region 30-40 years ago, but has seen a decline. In everyday speak I prefer "svigerinna mi" unless I want to emphasize the possessive, then I'd say "min svigerinne" (I use the masculine possessive for the indefinite form, even though I consider the noun a feminine, it is not considered a grammatical error.)