Bruce has never thought about adopting another kid after Tim. Obviously having as many Robins as possible was a good thing since they could help him have a wider range around Gotham, but that meant that supervillians could use the Robins against him, just like what happened with Jason, destroying his mind till he hated Batman, making Bruce think that Jason was dead. Yeah, it was enough for him.
You've heard stories about Batman and Robin, sidekick of the superhero, fighting crime together and all of that. You've never thought you would actually have the possibility to be one of them.
You live in the streets feeding yourself by the food some restaurant's owners give you sometimes if they feel kind enough, but that's not always the case. You aren't even 18, yet, you've felt how starving could be and what it does to your body.
Bruce was patrolling Gotham when he found you passed out in an alley, starved and cold from the constant rain of the city, it was at that moment that he decided to take you in.
That's how you found yourself in a house, on a comfy bed with food on the nightable and Bruce who was sitting on a chair looking at you. "Are you alright kid? Did you get hurt somewhere? I found you on the streets passed out, Gotham it's not a nice place to be a stray, what's your name?"