Yes! I do love the idea of personal Twitter account hosted by the main character! Go for it! And yes, you will need to get started NOW, in order to build up a network and a decent number of followers that can be notified when you share the truth and the publication of the novel.
Kill-your-darling moment: Have you researched the number of accounts with a similar name or username. You might consider re-naming Anna to something more unique.
Make sure you follow me as soon as you have everything set up.