Who was Abraham’s first convert?
The Lord said to Abram: Go out from your land, your relatives, and your father’s house to the land that I will show you. 2 I will make you into a great nation, I will bless you, I will make your name great, and you will be a blessing. 3 I will bless those who bless you, I will curse those who treat you with contempt, and all the peoples on earth will be blessed through you. 4 So Abram went, as the Lord had told him, and Lot went with him. Abram was 75 years old when he left Haran.
Sarai, before God changed her name to Sarah, had really no choice but to go with her husband wherever he went.
Lot, on the other hand, decided to go with Abram (Abraham) because he believed in the message that Abram got from God, that He who spoke to him was the true God. That made Lot the first convert who followed the true Living God who is Yahweh.
2 Peter 2:6-8
6 and if He reduced the cities of Sodom and Gomorrah to ashes and condemned them to ruin, making them an example to those who were going to be ungodly; 7 and if He rescued righteous Lot, distressed by the unrestrained behavior of the immoral 8 (for as he lived among them, that righteous man tormented himself day by day with the lawless deeds he saw and heard)