Honestly, it's a journey of many years. It all kind of falls together like dominos would.
As a child raised a devout Catholic, I considered entering religious life. I was drawn to the idea of living in dedication to God, veiling, living a life in service to others. By the time I was around thirteen, I found a lot of flaws in the Catholic institutions I was in. My religion teachers weren't theologians equipped to answer my questions or even that familiar with catechesis. I didn't believe in original sin, I didn't believe in Jesus' divinity (though I respected and revered him), and as far as I was concerned, the Catholics I knew cared far more about heaven and hell than they did the people around them. The punitive nature of Catholicism was drilled into me deeply. I convinced myself that I was unworthy of God's attention and love because of my sinful nature, this idea that I was naturally inclined to choose evil, specifically because my parents had sex to conceive me. I believed it. I used it to justify bad behavior, and hurtful decisions. "If God made me sinful, why bother to correct it?" kind of mindset. Eventually, I lost interest in the formal Catholic faith I was part in at a Catholic elementary/middle/high school.
When I was 16 I came across a video of a young boy reciting a verse from the Qur'an. I'd never heard the Qur'an out loud before. I didn't even know it was something to be recited rather than read. I knew next to nothing about Islam. But the recitation (it was 25:61) awoke something in me. Looking back, I realize now that hearing it reminded me of my fitra. It called me back to my original inclination, it drew me to seek more about the Qur'an, to understand and to learn as much as I could about the beautiful "music" I had heard. Just hearing a single verse out loud deeply found its way into my spirit. When I told my mother I thought I wanted to convert as a teenager, she threatened to throw me out of the house. At the time, all she knew of Islam was stereotypical. Terrorism, as you can imagine. I didn't blame her for being frightened, so I left it alone then. But when I got to college, I met other Muslims and began to spend more time with them. I began to do community service alongside them. Eat and drink and fast with them.
I started to read what I could, and I found that what I did read resonated with me deeply. No original sin in sight, our decisions are our own. No priests to be mediums for Allah-- I place my forehead to the ground and the Almighty listens to me himself. Paradise lies beneath my mothers feet, and a father's entrance into jannah is found with his daughters. If a woman miscarries, her lost child pulls her into jannah- even if she was destined for hellfire. Above all, the belief that we are indeed created good. Even if this life is a test for us, one with beautiful trinkets we have to fight to keep away from, we are called to choose good. Allah's mercy is so all encompassing that even if our sins reach the clouds, we only need to ask to be forgiven. Allah says that every step we take towards him, he comes to us running.
When the angels ask Allah (swt) why he created us when we're prone to destruction Allah replies, "Because I know what you do not." I cry thinking about that hope Allah has in us. I am honored and content to be part of a religion that blesses us just for smiling at a stranger. That rewards us as though we've done a good deed just for thinking about doing one, then rewards us even more when we actually do it. Dhikr with tasbih focuses me more on the divine than the rosary ever did. I am proud to follow a Prophet who visited a woman who threw trash on his doorstep every single day, because the one day she didn't he thought it was strange- and found her sick. His concern for her brought her to Islam. When once I had convinced myself I was inherently evil, Islam reminded me of my closeness to Allah, how he is closer than our jugular veins. That when we remember Allah, it's Allah remembering us. Allah chose me out of millions to be a Muslim, alhamdullilah.
In the end it was very... keep all the Prophets. Keep the Torah, keep the Psalms, the Gospels, keep Mary, keep Jesus (sans divinity), add Muhammad. And that was it. And I'm content, comforted, and happy in community. It's what fills my spirit with love for Allah, for my family, friends, and humanity. That's not to say I didn't reconcile with Catholicism as a theologian, but personally, I'm happy within Islam.