I feel like LO is behind. he just turned 5 months nd he hates being on the floor at all so when i do he just lays there and gets mad. His legs are super strong and he loves his jumperoo, he also just found his feet and will do anything to get them in his mouth. yet he wont roll, sit it up or do anything else. he is very attentive and loves attention but he isnt making any sounds except for getting mad.
I wouldn't be really concerned about it unless your pedi starts getting worried. My friends baby was like that too. Didn't roll over till 7 months (shockingly) and she always hated tummy time. But she was crawling at 11 months and walking by 14 months and seems to be all caught up now.