Is it permissible for me, at 15 years of age, to perform Umrah on behalf of my deceased father, knowing that this is my first time performing Umrah, and what are the conditions and the method?

As long as you have not performed the obligatory Umrah for yourself, start by performing an Umrah for yourself first, in accordance with the Prophet's (peace be upon him) saying to one who wished to perform Hajj on behalf of another before performing it for himself: "Perform Hajj for yourself, then for Shubruma." Hajj and Umrah are the same in this regard. After completing your Umrah, go outside the Haram boundary to Al-Hill (such as Al-Tan'im) and enter into Ihram for an Umrah on behalf of your deceased father.

Description of Umrah: 1. Ihram (Ritual Consecration): From the Miqat, with ghusl (ritual bath), perfuming, and wearing the izar (lower garment) and rida' (upper garment). Then, enter into Ihram after prayer (obligatory or supererogatory) and say: "Labbayk Allahumma Umrah (Here I am, O Allah, for Umrah)." It is recommended to frequently recite the Talbiyah in the form: "Labbayk Allahumma labbayk, labbayk la sharika laka labbayk, inna al-hamda wa an-nimata laka wa al-mulk, la sharika lak (Here I am, O Allah, here I am. Here I am, You have no partner, here I am. Indeed, all praise, grace, and sovereignty belong to You. You have no partner)" until the start of the circumambulation.

2. Tawaf (Circumambulation): Upon reaching Makkah, begin circumambulating the Kaaba starting from the Black Stone, seven rounds. Then, pray two rakahs of the Sunnah of Tawaf behind Maqam Ibrahim (or in any other place during crowd conditions).

3. Sai (Ritual Walking): After Tawaf, go to Safa and ascend it. Then, proceed to Marwah. Going from Safa to Marwah counts as one round, and returning from Marwah to Safa counts as another round. Continue this until you complete seven rounds, with the seventh round ending at Marwah.

4. Tahallul (Deresecration): After Sai, shave your head or shorten your hair; shaving is preferable. With this, your Umrah is complete.

For your father's Umrah, you will do exactly as you did for your own Umrah, but when entering into Ihram, you will say: "Labbayk Umrah an Abi (Here I am for an Umrah on behalf of my father)," and the Ihram for it will be from Al-Tan'im or any other place in Al-Hill.