The Verdict: Need More Info
You are at the start of the residence clock, so this is a matter of time. Work out whether five years, two or one applies to you, and keep your residence card continuous.
Five years is the general rule. Two years applies to nationals of Latin American countries, Spain or Portugal, to direct-line descendants of a Mexican by birth, to parents of a child who is Mexican by birth, and to spouses of Mexicans living together in Mexico. One year applies to people adopted by Mexicans who apply before turning 19.
You already hold permanent residence, which is what the ministry expects of applicants, so only time stands between you and an application.
You will also sit the foreign ministry's exam on Spanish, Mexican history and civic culture, which is a common reason for refusal. The formal renunciation of your other nationality is asked for only once the ministry has decided to grant.