[RCF]

Well, even if she noticed the change in Krish, what was the hurry to attempt to have a child right then? Yes, she realised Krish has changed, and the games she has been playing with Desai might backfire. So her offer to have a child with Krish at this moment may not even a genuine offer, and more of a delaying tactics, or may be a bribe to dissuade Krish from his chosen path.

This one is tough question and we can only predict Meera's thinking.

My guess why she delayed all this time:

She has delayed the child because she has been distant with Krish, vexed with his fantasies and was getting closer to Desai for pleasures and intimacy. So she doesn't want a child at this time especially when Krish is not much into her with out fantasies.

My guess what's changed after Alpine heights:

She has experienced for the first time how would it be to have a child with Krish by fore playing with Desai and it was a moment of revelation to her on how much she liked it and how much she started craving for it, It is one of the reason why she changed her plan and confessed to Krish rather than because Desai asked her to confess it. She realized that only way she can go forward with Krish and her life would be to have a child which would make both the couple to forget Desai and take him out completely from their mind. If you remember she proposed the child part even before Krish mentioned to separate so its clear her intentions are genuine, not with the fear that Krish will leave her.

~RCF