Question: How do two sims become BFF? (Sims 3)

Hello! This is my first time posting here. I hope I'm not breaking any rules... most of what I'm seeing are Sims 4 posts so I'm not sure. Any way, I hope someone can help me.

Two of the teenagers in the household have the become BFF with each other wish. They have been Best Friends for a while now... in fact they are old friends. I had read that after 2 days of being best friends they would become BFF but nothing has happened yet. I have the sim lifespawn adjusted to 192 days now to longer stages... I don't know if that's affecting it.

Can anyone tell me if I still can get them to be BBF? Or should I use Master Controller for something like this? Would it still count for the wish?

Thank you.