Baby has days and nights mixed up.

My daughter will be 4 months on the 12th this month. She’s got her days, and nights mixed up. She still sleeps through the night. It’s just so hard to put her to bed now. She would go down for the night at 9-9:30. Then I’d wake up around 6 to start my day. I make her a bottle, then I change her then I feed her. But now she goes to bed at 2-2:30 in the morning because she fights her sleep, and sleeps through the day. When my parents watch her so I can work. The only time she’s up is to do tummy time, bath time, feeding time, and diaper changes with them. It’s hard as well because it makes no sense that she has them mixed up. When I’m with her she plays all day, and only takes 2-3 naps. What can I do to fix this ?