Why has she stopped saying hi to me, but prefers to say morning?

This girl has shown interest in me, but she is a passive and reserved girl and she told me, but before we had a proper talk, I use to always say hi to her and ask her how she is first (she’ll wait for me to say it), but since we got talked to each other one to one, she says morning to me when she sees me, not a hi anymore and also, she also tries to greet me first and not wait for me anymore. When say hi, she says miring. Also when it comes to messaging.
Why has she stopped saying hi to me, but prefers to say morning?
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