DD is nearly 5 months old and already wants to crawl. She used to happily kick on her play mat/baby gym for ages lying on her back, but now tries to roll over immediately I put her on there. (Can't quite roll unaided yet). When on her tummy, she shuffles around to reach toys, but is desperate to crawl, legs pumping frantically. After 5 minutes she gets frustrated/crying. The cloth surface just rucks up when she moves, so impedes her. Was thinking of trying yoga mat with a rubbery surface so she can 'grip' more. Any advice for surfaces to learn on/ different play mats available/other activities to try etc? She also wants to sit up on her own already.