Re: whistle
Yes, keep going through the same lesson. Whenever you feel you are ready to move on.
I take breaths through my mouth. If you feel like you are dying, you should stop and get your breath back and then resume wherever the CD is at.
Take deep breaths, not fast and shallow. Try that and see how it works.
I'd say a few months, yes.
Keep singing!
Jolly Jake
____________________________________________________________________________________________________________
"Work very, very hard - be grounded, be passionate about what you do and find the thing within yourself to make you want to be you. Go beyond me, be yourself, say what you want to say." - Josh Groban (Paraphrased)