Listen carefully to see if there is any obvious air leakage sound at the flute mouth when playing. If there is, there is something wrong with your mouth, which will happen to you from the beginning.

Judging from your situation, this is the problem. )

When playing, pay attention to swing the mouthpiece in the right position first, and it is forbidden to press the mouthpiece more than half with your lips.

Of course, you can't press it too small. Preferably about one third. You have to find the feeling that suits you.

Secondly, when playing, laugh and vent. The upper lip is slightly ahead of the lower lip, and the breath goes down without leaking (you can feel it by blowing with the back of your hand).

It's stretched. Don't blow it. It will deform.

Don't feel strange posture, just get used to it ~

It could be the flute.