It can be done in many different ways. You can change the font size and color under the "Appearance" section within a new Action for the text object. Or add the Tween behavior to the text object, and create an Action using "Tween" options within the Tween section for the text object, to change the size, location, etc. Whether that is multiple "Tween (one property)" actions, or other Tween options.
EDIT: You could could also do "Tween (two properties)", and tween height, length. Under "Size or Scale" in the Property dropdown on that menu.
EDIT 2: I hope that makes sense. I'm extremely tired at the moment, and need some sleep. It might be worth making a small sample project, and playing around with the Text "Appearance Options", and the "Tween" Options(after adding that behavior to your Text Object). Experiment until getting the desired result.