My question involves a marriage in the state of: California

My wife wants to get a divorce. She appears far more motivated to expedite things than I am and says she doesn't want my money. However, to avoid the possibility that she changes her mind about the money, I've suggested a post-nuptial agreement as the first step - before I file. Would this be the best route to go, or can the full settlement agreement be done and notarized prior to the initial filing?