Starting with a Flashback
Starting with a flashback is an option, but it might not be the best option for you. It just doesn’t make sense when looked at critically, particularly in opening. You can’t have a flashback to a storyline if you haven’t established a present situation or circumstance. This is totally different from prologues, which are acceptable, and care should be taken not to confuse the two.
For a flashback to be more realistic, there has to be an already established circumstance that would relate to the past you are flashing back to, while prologues merely point to some information that explains situations that are yet to come or gives a pre-emptive reason for their occurrence. The act of starting a script with a flashback appears even more unattractive when being read. Industry readers want to be thrust into the present as soon as possible, and a flashback might be off-putting for most of them.
At the same time, using a flashback early on served its purpose in Penny Marshall’s 1992 sports comedy-drama, A League of Their Own, staring Madonna. The first scene opens with the veteran baseball female players entering the Hall of Fame as memories rush them before the movie then flashes back to how the women got to that point. Even in this scenario, however, there was enough time for the viewer to establish an understanding of the present state of the women and their league before the flashback began. It serves more to show where they came from and the deep history as opposed to slowing down the story.