don't worry so much. it really takes time. why not get the push toys and let your child practice it. maybe it will help. for sitting upright you can try get a baby chair. for tummy time try to get some interesting toys for your child to play during tummy time so child won't bored. for baby tooth wise i got an infant who is already 12 months still no teeth. hehe. so don't worry mummy.
hi mummy don't worry about it .. my baby is 13months old .. hates tummy time .. prefer support standing 😂teeth just came out after 1 year old .. don't worry about it. ..