Sleeping On Tummy

Hello Mummies, my 1.5 months LO had been sleeping on her tummy since last week. Initially i thought she had issue sleeping alone, but realised she doesnt like to sleep on her back. Its like a 1 hour vs 3.5 hours sleep.. Elderly says it's okay to sleep on her tummy. But i read online that its not recommended. Can mummies pls advise if your LO is the same, or anything can i do?!