Is it correct?
She doesn't want to die BEFORE SHE IS 100 years old??

Question

Answer

Yes this is correct.WE don't use FUTURE tense after the words "before" or "after" or "when."
for example "When I am 30 I will go abroad" this is correct despite the fact that is talking about a future event.

Answer

Who are you talking about?

It is correct. However, I would not use capitals and you should either end with a period or exclamation mark.