Baby milestones

My baby is 4 months old, this is my second baby and my first baby hit milestones right on time if not early. She’s a very fast learner.

My now 4 month old smiles all the times, talks to us and bites on her hands and can hold her own head steady while sitting or being held in a standing position.

But she doesn’t always pick her head up very high during tummy time, and she doesn’t grab for toys or put them in her mouth.

We do have a dr appointment soon bc she just turned 4 months like 3 days ago and I will ask her doctor but has anyone else had this happen??