My daughter is 6months old and still isn't rolling? She can sit unsupported for short periods of time before becoming unbalanced but she's not rolling at all yet. She hates being on her front and will cry within seconds of being put on her front, she'd much prefer to be in her walker or jumperoo. I'm worried that she's behind on her development? Is it normal for her to not be rolling yet? I'm probably comparing her to my son to much since he was rolling at 4 months, crawling at 7 and walking by 9 
I've tried contacting my health visitor on a few occasions but she never contacts me back or I'm told I'm on the list for a phone call but she's extremely busy. 