Phoebe

From what you could remember, Piper had been with a guy for a while when the show started, and while you could remove him from the equation, him being a Warlock is what helped transition the girls into the magical world.

Prue ,meanwhile, came across as cold and indifferent to outsiders, and her family sometimes, and it would take longer than the other two to crack her shell, so she was unlikely to trust you initially, regardless of if you were dating.

Which left Phoebe, which left you with a small shard of disappointment at yourself since it gave off the impression that you were going after her because it she was the easiest to get to. You reminded yourself that the people of the universe weren't characters anymore, they were real flesh-and-blood people with feelings and mortality. You made a mental note that you would try your best to keep Phoebe happy.

With your decision made, you realized you had one last thing to account for: an identity.