If you cleared CTET in 2018 under the OBC-NCL category, that certificate remains valid for eligibility as long as CTET validity rules allow it. However, for KVS PRT recruitment, your category is decided based on your current OBC-NCL status, not the one you had in 2018. Since you mentioned that in 2025 you no longer fall under OBC-NCL due to your father’s income, you will be treated as a General category candidate for KVS recruitment. You can still apply for the PRT post, but you must apply under the General category and will not get OBC-NCL reservation benefits. The CTET certificate is still usable; only the reservation category will change as per your present income and eligibility. All the best! https://competition.careers360.com/articles/kvs-recruitment
Yes, you can choose Mumbai as your CTET exam centre even if you select Assamese as your language paper. The exam centre choice depends on your current location, not your state of residence. However, make sure that Assamese is available as an optional language while filling the CTET form once selected, your center and language choices are independent, so you can write the exam in Mumbai with Assamese as your language. Hope you understand.