my daughter started to roll at 9 month 1 day and now she is 9 month 21 days old. But she is rolling only when i encourage her by showing toys, and put a lot of effort to make her do so. she is not moving forward. she sits when i make her to sit since she was 7 month old. She does not take much of her weight on her legs. When will she crawl. is there any problem?