Am I a Catholic if I received private instruction instead of going through RCIA?
I was raised Baptist, and when I entered the Catholic Church I did not go through the RCIA program. My priest privately instructed me and then received me into the Church outside of the RCIA process. Am I a Catholic if I didn't go through RCIA?
Yes, you are indeed a Catholic. Your priest’s method of receiving you into the Church is actually preferred for non-Catholic Christians. RCIA’s primary purpose is to catechize and sacramentally initiate those who are unbaptized. Many parishes lump adult catechumens (non-Christians awaiting baptism), candidates (non-Catholic Christians awaiting confirmation), and adult confirmands (Catholics seeking confirmation) into the same RCIA program for practical reasons. This can be done, but your priest’s method better conforms to the purpose of RCIA.