Ok, let's take the questions one by one.
So, I had a Christian background as a little kid, and spent a lot of time not being religious/spiritual at all.
The Lady found me rather than me finding her. My friend (I'm gonna call her Hawk here) already worked with Her. Hawk already worked with the Lady, and the Lady started poking at me while my friend and I were talking. I was a little confused at first, admittedly. Hawk was willing to facilitate a conversation, and that's how the Lady and I got to talking. The fight happened later on. The Lady noticed me and decided to reach out because she thought I had potential. Another god from a different pantheon also noticed that same potential and wanted proverbial dibs. Hawk had to call in someone else to get them to quiet down and move the shouting match away from where it was causing me a panic attack.
This was about the same time I learned that I was real sensitive to the energies of other people and to those of the gods and goddesses. Hers felt safer to me, I guess? It's a lot of personal experience on that front for me.
It took a good month of thinking on my own to make my decision, and honestly it was a rather literal leap of faith for me. It's ...hard to explain? My intuition guided most of my decision making on that front, and with my practice in general.
I hope this all makes sense.