My little girl will be 4 months old. She HATES tummy time but even still is very strong. Hold herself up very well and is supported sitting as well. She loves her seated walker. She has a great time Playing with her toys and scooting backwards through the living room. Shes been using it for about 2 1/2 weeks. I had a gal pal come over and say she was to young to be in it. But she gets fussy laying on her back and i cant hold her 24/7 and i dont want her to get a flat spot on her head. Am i wrong to continue letting her use it?