I grew up in nominal Protestant home, in a heavily Protestant area of the United States.
We went to church simi regularly at first, then occasionally, then not all.

When I was in my early 20s I wanted to start living life as a Christian. So, I asked God to show me which church he wanted me to join, and he made it clear that it was the Catholic church. I didn't took that to mean Catholicism was absolutely true and all other churches were wrong at the time.  Just that God wanted me to be Catholic. I saw it as no different then any other denomination. It was right for me but someone else might need to be baptist or Methodist or whatever.

However, my Protestant friends and family didn't see it that way. They seemed to think any church was ok, except the Catholic church. And they routinely challenged my faith, making all kinds of accusations against the Catholic church. So I decided to do research and see if these accusations were true. I began reading the bible, looking into history, reading the early church fathers, and educating myself on what the Catholic church teaches.

Over time I came to the conclusion that Catholicism is the absolute truth, and Protestantism is in serious error.