Always speak to paediatrician if concerned
i totally get that, it's so easy to compare, but every baby is on their own timeline, so try not to stress too much! this is what the 'Heal Baby Care App' mentioned… hope it helps! "It's completely normal to feel concerned about your baby's milestones, especially when comparing her to others. Every baby develops at their own pace, and some may hit milestones earlier or later than others. Rolling over and sitting up can take time, and it's okay if she's not fully mastering them yet. For weaning, try offering a variety of textures and flavors to see if she responds better to certain foods. Remember, according to the American Academy of Pediatrics, the focus should be on creating a positive feeding experience rather than rushing the process. How does she seem to feel during mealtime?
Sitting without support is a skill for 9 months on average. Sitting with support is great for 6 months. Rolling can be due to lack of interest or possible hurt if she banged her head couple of times against hard floors and got upset by it, continue training with her for rolls. Does she open her mouth for food? If she makes faces then it’s fine, you’ll find some food she’ll love. It’s all weird and new to her so it’s all fine. Ensure she’s ready for food:she should open her mouth when food is in her view, grab food or spoon in front of her Don’t compare her to some babies or yourself to moms who say their babies do this or that when in fact they don’t use proper terminology or train babies to start sitting unassisted at 4 months when on average the baby is not developmentally ready. Don’t give yourself or her the complex of “I’m not good enough” because you think some braggy mom’s kid does something earlier that the average kid. She’s doing great according to your message.