Kindly refer to the following link(s):
How 2 prevent our kids from wanting to celebrate birthdays & Create balance for them?
Can we accept Birthday Gifts? | Sheikh Assim Al Hakeem
Can I give someone a gift on his birthday without an intention of celebrating it?
What to do when our kids get upset because we don't celebrate their birthdays?
Can we wish people 'Happy Birthday' | Sheikh Assim Al Hakeem
Cakes
Are we allowed to have cakes for birthdays?
Wedding cakes vs Birthday cakes & Ruling on selling Cakes
Ruling on Celebrating the Prophet's salla Allahu alaihi wa sallam Birthday
Ruling on celebrating the birthday of the Prophet (mawlid)
Celebrating the Prophet's birthday (sallalahu aleihi wa salam)
Celebrating Birthdays, New years, Mother's Day, Father's Day etc