بسم الله الرحمن الرحيم
Imam Bukhari (may Allah have mercy upon him) has recorded this Hadith in Al-Adab al-Mufrad:
عن بن شهاب قال : كان الرجل إذا أسلم أمر بالاختتان وإن كان كبيرًا (الأدب المفرد ، رقم : 1252 ، باب الختان للكبير).
So, the scholars of fiqh have explained that a person who accepts Islam in late age it is wajib for him to undergo circumcision if he can bear the pain, it is sunnah muwakkidah and necessary. Hence in the question mentioned above, it is sunnah for you to undergo circumcision. You should undergo the circumcision by any expert doctor. Here it should also be noted that circumcision is not the sunnah of marriage rather it is the sunnah of Islam. Hence if you do not marry then too this ruling shall apply.
Allah knows Best!
Darul Uloom Deoband