How do I shift my baby's bedtime?

[ButteryJam]

LO is 13 weeks and had a bedtime around 9pm, which had now shifted to 12 midnight! This is due to a late A&E visit. So she is doing 12 midnight to 12 noon. How do I shift it to 7pm - 7am without severely upsetting her. She is already a very fussy and upset baby. Thanks!

Could you wake her up a bit earlier every day, which should make her ready for bed earlier each evening?

It's really difficult to wake her up earlier as then she's in a mood! And it takes forever to put her back to sleep. I'm going to have to do something though!