Is there any reason to hold out for a non Java/JVM Android development experience? I remember rumors of Dart or Python, but those seem to have died.
It is heralded by the Dart team, entirely independently from the Android team. AFAIK, they are just shopping for a problem to solve with Dart now that they are not going to be able to ship their VM with Chrome.
Flutter started with JS as the scripting language. The Dart team is certainly lending a lot of support to Flutter, because of the promise of a compelling mobile story for Dart.