I am 23 years old, and I haven't played any wind instrument.
I bought a Thomson Flute. I don't think that this is an expensive flute.
I followed all the basic tutorials in youtube. All of them started with just playing a note using the head joint.
And I noticed all of their sound are full. Mine is quite airy, like there's a hissing sound on every note.
Is this normal? I can make the head joint produce sound, both closed and opened.
I can make the Mary had a Little Lamb tune using just the head joint.
But is this the correct sound of the head joint? Any tips on how can I make it sound fuller?
Also, another question. In those tutorial, the starting note is B. But when I try to place my fingers on the same keys the tutor does, It sounded almost like a C#. Is this also normal? Or should I just adjust the head joint?
I am confused right now. Please help.

Thank you.