I am a male 14 years old and I can whistle quite well, but if my voice will change will I lose the ability to reach them? And high notes in particular??
There's no reason why you should not be able to whistle well after your voice breaks. The voice is produced in your throat. You don't whistle from your throat, it's only the air that comes from there. The whistle is produced from your lips, which won't have much effect on the depth of your voice.