We painted our apartment 4 days ago and it still smells like paint but its dry. Is it safe to sleep our 2 month old baby in the room?

I would wait until you can't smell paint fumes anymore.

If possible, close the door and open the windows. Let it air out for a few hours. If it's cold where you are, the cold air will do wonders for airing it out. After you close the windows and let the room heat up again, see if it still smells like paint.