My baby girl is 18 months old and always sleep past 3am

there is a sleep regression at 18 months. but do rmb that follow the 3 hourly sleep schedule don't over stimulate them. try using a carrier to calm them down and make them sleep

she will usually have a short nap between 4-6 plus for an hour and 30 minutes..

oh not that's not very good. how's her sleeping routine like?

after which, she will continue to play until past 3am