Depends on your baby my daughter is an early starter shes 5 months on 27th and has been laughing smiling and rolling from around 4 months. She's also teething and is starting to stand some are just fast learners and some take time
We get lots of squealing and smiles but have only managed 1 giggle so far out of our 5 month old boy. I’m not worried 🙂 some babies will giggle earlier than others, the same as other milestones!
Maybe that you just have not found what makes her laugh - we noticed with our son that more stupid thing you do, the more it makes him laugh like picking up and keeping in the air, playing with a Muslim cloth hide and seek 😱😅 he likes living his life dangerously 😂