I know this is a very old thread. I am a 64-year-old woman and never learned how to swim. I decided it was time. My biggest fear and problem is putting my face in the water and trying to do the breathing that is required for freestyle swimming. I always get water in my nose.
I finally decided the best thing for me at the moment was to purchase a small dive mask which covers my nose as well as my eyes. This has helped me greatly and so in the breathing exercises I have to only use my mouth for exhaling underwater. But the bobbing method that you talk about is extremely helpful. I thank you very much for posting this!
It is very hard for me to keep relaxed breathing. But today I was able to do 7 full laps (350 yards) in a row!