Have I failed?

Chi

My 7 month old doesn’t have any interest in sitting up or crawling. When we wake up I put her on tummy time and when she’s done she just rolls. So far I’ve seen her get up on her knees but it’s only for her to roll over, I feel like I’ve failed some how. I see other babies crawling and on the go and mine just wants to be standing or in her walker. She has very strong legs but still I’m starting to worry. 😓