Why my 3 months old boy does not like to play with toy rattles?

At 3 months old, they don't have much vision at all - things are still pretty blurry to them and they don't really have much gripping ability yet, hence they probably won't like toys like rattles! In fact, most babies do not need toys until they're at least 6 months old - they're happy enough just with your company, listening to your voice or songs :)