Flute Bb key help, notes don't sound as clear?

-I've been trying to learn flute by myself, and it is pretty hard, but I can make a few sounds out of the flute at times. However I've noticed that certain notes sound less airy when I press in the Bb key instead of just the thumb key.



In fact I can't play a G note at all unless I press down the Bb key, then it sounds crystal clear. Is this a fault of my flute? I've noticed the Bb key only depresses halfway when I press the key to it's right, should it shut completely in this situation?



Any help would be great, as I've got no clue on whether my flute is faulty or if I'm just not getting the airflow right!This is slightly unrelated, but when I first started learning flute, my mom made me practice with only the mouthpiece, trying to get clear airflow and a 'nice' tone. Then after a while i put it tgether , and it was much easier. And I think it's your flute..does it look broken?
I have the same problem, but it takes prac.