Sometimes children find it really difficult to crawl. It might be because they lack body on body rotation movement patterns or upper body strength or tone. They may not be able to cross the midline easily or may have delayed protective ( positive supporting) reactions that you use to save your face when you are about to fall. Some children have balance or vestibular issues that make them fearful to put their head down. In Daisy's case, she had flat head syndrome (plagiocephaly) with reduced neck movement (torticollis) and this affected her motor skill development in her first twelve months.
Have a look at these lovely videos of us encouraging Daisy to link sitting to tummy and vice versa; high kneel to develop better control around her low back and tummy; practicing her arm parachute reactions; achieving all fours and beginning to crawl, once her neck range is all okay.