My DD is 8m today. She could sit up by 4m, could even "stand up" for a good while propped against the back of the sofa by 3m, she babbles, turns pages of books, is trying (and failing) to crawl...
Should I be worried that she can't roll over front to back? She does try, but keeps her arms too low, so it's impossible. She can roll back to front easy-peasy, which is supposedly more difficult.
We always joke that she's lazy, because she'd always fall asleep doing tummmy time, and doesn't bother reaching for toys, settling for something closer/easier.
Just PFB worries?