Previously, my baby wakes up at 10pm, 3am and 5am to drink her milk. But just last week, she doesn't wake up anymore and enjoys sleeping longer hours instead. Is this normal to all babies?

Be happy and get your well deserved sleep! My son used to sleep through the night but has recently started waking up at least once for milk. Your baby has probably recognized day and night time, and don't worry if he is hungry or not, he'll wake up and cry for milk if he is ^^ Meanwhile, enjoy this phase!