The keyword here is "nearly in", that is to say nearly starting her fourth decade. Once you reach 30, you have 'finished' living for 3 decades and you start your fourth. It's kinda like how we are in the 21st century even though the 2000s, relatively speaking, just started and it is no where near the year 2100 yet. Semantics, i know, but thats just how english works sometimes
Edit: also, its troubling that people are starting to rely on ai for trivial matters like this. It's like giving up on thinking all together and asking someone to just hand you the answer
Besides, GenAI is in and of itself not infallible and there is always a non zero chance that it they generate a wrong answer
if you have ever seen ai generated images/artworks you know what i mean