You are really doing good at 4 months.  You aren't that needy compared when you are 1 and 2 months old, you entertain yourself when you are up by cooing and even giggling.  You can hold your head real good during tummy time, you can grab your pacifier from your mouth and just grabbing what is near you like the toys hanging from your play mat.  Been sucking your 2 fingers(index and middle fingers).