Aiyooo, I totally understand your worry especially first baby kan! A few of my mum friends had babies yang took their own sweet time with rolling and tummy time activities, and the paediatrician told them the same thing, some babies are just slower developers but still completely normal. Alang-alang the doctor has already given you the green light, I'd say trust that, but of course keep encouraging tummy time daily (even just 10-15 minutes la) dengan toys or your face to make it interesting for her. Sabar sabar, some babies suddenly decide to terbalik one day and then you can't stop them!