I became a Christian in college (1980). Not sure if you consider that an adult conversion. I was raised in a very liberal protestant denomination and assumed I was a Christian, so I joined a Christian fellowship group on campus at the beginning of my freshman year. I very quickly noticed a huge difference between these people and the people I grew up with in the church my family attended. I realized that I really didn’t even believe in God. I started meeting with the person who ran the group and started asking lots of questions. I read Josh McDowell and CS Lewis and other Christian apologists who were popular at the time. At some point in the middle of all that God tugged on my heart and I gave my life to Him.
I have similar elements in my story.
I liked Josh McDowell’s “Evidence that Demands a Verdict” and “More Evidence that Demands a Verdict”.
I tried to find an article I wrote about the evidence for Jesus claiming to be God Himself, which I even reposted here on FR but I cannot find it.