Most people stop growing in height around the age of 18 to 20, and this includes the hips. However, the pelvis continues to mature and widen throughout a woman's 20s, as it prepares for childbirth.
While the hips might not grow longer after a certain age, the width can change throughout a person's life. Weight gain can lead to wider hips, and bone density can affect hip width as well.
Note: The information provided here is general and does not constitute medical advice. It's always best to consult with a healthcare professional for personalized guidance on your health and development.