Hello! My son started holding his head up (without assistance) around the 4 month mark. Just for some perspective, he was quite small at birth and remained in the very low percentiles for height and weight. So...his development may have been a bit behind other boys. But, he did do it. And, once he did, he enjoyed sitting in the bumbo/bebepod seat.
FYI - he sat up on his own (with no assistance from me) on his 6-month birthday. Just a little something for you to look forward too.