Is it permissible to shave the sideburns that have grown without a full beard for someone who has reached 17 years of age?

If "as-sawalif" refers to the hair of the 'idhaar (sideburns), which is the hair adjacent to the ear, then it is considered part of the face and falls within the boundaries of the beard. Therefore, it is not permissible to shave it. The Fiqh Encyclopedia states that the 'idhaar is the hair that grows adjacent to the ears, between the temple (as-sudgh) and the cheek (al-'aarid), and it is part of the hair of the face. Ibn 'Abidin also explicitly stated that the 'idhaar is part of the beard and its rulings apply to it. In the fatwas of the Permanent Committee, it is mentioned that the 'idhaar refers to the beard hair that grows on the sides of the face.