I was Baptized a Non-Denominational Protestant in my teens. Later, I drifted away from my faith. But I was always interested in Catholicism since they were so different from what I grew up with. When I began studying Catholicism I found a faith I responded to. It took a couple of years and a few trys at RCIA before I finally went through with it, and as of this Easter I’m now officially Catholic!
Don’t worry too much about RCIA. My main problem was that it was all so basic, I felt like a college kid having to sit through kindergarten. But I understand that many people need that basic level and it also helps to make sure that there aren’t any holes in your foundation of faith.
If the parish you attend is big, it will likely be led by a lay person who specializes in RCIA. If it is a small parish, you may get lucky, like me, and have an actual priest teach the class. Having tried both, I recommend the small-parish approach. It just feels more personal.
You say you were christened in the Salvation Army. Do you mean that you were Baptized? If so, then you will not need to be re-Baptized. I know that the Salvation Army likes to do “dedications” and not Baptisms, so if that’s what happened to you, then you will be Baptized at the end of RCIA, at Easter Vigil. Otherwise, you will be Confirmed and given first Communion.