Drupal 7 has a much longer lifespan than the (already pushed back) official date, and Drupal 8 has an essentially infinite lifespan because it can update in-place to Drupal 9 easily and the same will be true of Drupal 10, 11, ∞. There's no reason to rush an upgrade— but there's no reason to wait either.
Agaric is excited to announce online training on Drupal migrations and upgrades. In July 2020, we will offer three trainings: Drupal 8/9 content migrations, Upgrading to Drupal 8/9 using the Migrate API, and Getting started with Drupal 9.