You can't omit the 'it', or your sentence basically means that you won't go deaf before you die (i.e. you will be able to hear as normal).
thank you so much~I'm not completely sure I understand what you're asking...
If you write "I heard this sentence from my teenager, and will hear it until I die." then it means that you will hear that sentence echoing around in your head until the day you die.
If you write "I heard this sentence from my teenager, and will hear until I die." then it means that you heard something from your teenager, and you will be able to hear in general (the birds singing, your noisy neighbours, etc.) until you die.
The 'it' is definitely necessary.
Is that what you mean?
Happy to try to help, jjshin.thank you so much~
I mean I hear something in general, like brids singing.