For ABMs as it stands right now, you can go after you complete your first assingment post Tyndall. They want you to start your rated development and to do that, you need to start your flying gates. They may ask for more volunteers, much like the test UAV class example; but they only took 1 ABM in that case. ABM rated managment needs bodies, so if you're just getting classified as an ABM you'll have to wait awhile. That being said, once you've completed your IQT/MQT in which ever jet, let your boss know what you want to do and make sure your developmental plan (ADP) reflects (realistically) what you want to do.
Jonesy