Any and everytime my baby cries he has full on tears since he was a newborn. He's 4 months as well
Mine has tears if she is tired and yawns big lol but mine has had tears fully for a while she is going to be a good fake crier with those alligator tears when she wants something 🤣
My sister's baby boy didn't produce tears until he was about 5 months, but he was a super chill baby lol but if you are concerned just call your pediatrician, it's always a sigh of relief to hear from them that nothing is a cause of concern lol
My baby has tears if she cries more than a couple minutes, like if we're driving home and she cries in the car when I get her out she'll have some welled up tears but not like full grownup tears just one or two drops 🥺