I always planned on destroying the Dark Brotherhood. However, when I got kidnapped and held captive in the shack, I thought that Astrid was invincible (because I tried killing her once or twice and she only limped), so I played along and killed that jerk-off of a Khajiit. Now, I've entered the DB headquarters once, and I even walked by a guard and he said "Psst. I know who you are. Hail Sithis!" And I don't want that. I don't want to be a part of the guild. Can I still kill Astrid and begin the "Destroy the Dark Brotherhood!" quest?

Mercy bump. I need an answer!