Information about jehovahs witness and birthdays?

there are 2 places in the Bible, where it actually says 'birthday' one is at Gen40:20-22 and the other is Matt14:6-10. someone died at each of those 'birthday celebrations' and the ones that were celebrating their birthdays , did not worship Jehovah. so it only makes sense to me , that the birthday celebration, being started by pagans would clearly be something that we shouldnt do. a birthday is also kind of a 'self worship' day.. John the baptist was the one who was beheaded, wow all for a birthday, thats pretty sad to me...