I've never really considered BJJ a really good street defense, I think there are much better choices for defense but as a girl if shes attacked she would most likely get taken down easily so it might be a good choice. If you really want to teach your daughter defense teach her how to scream and make noise and call the police. But if you really want her to take martial arts get a combination of Jiu jitsu and muy thai.
As you can tell I'm actually not very sure of this but this is what I've heard and seen primarily.
Credit to ThaMuffinMan