4 month old barely bats or grabs at toys but all other milestones have been met. Anyone else experience this?

The pediatrician at her 4 month appointment this week seemed to feel it was odd but just said that we will track it and wait and see if she is doing it by the 6 month appointment. Should I be concerned? I am so worried because I feel like everyone else I talked to has babies doing it at 3 months or even at 2 months! We began working with her this week on it and she seems to sort of reach and will eventually grab at a toy but it is an ever so slight movement and a very slow grab that makes me wonder if is it even purposeful. She has begun to coo at toys but seems to prefer looking at us and us making faces at her and just doesn't seem that into toys. I just don't understand because she has developed normally in other areas.