birthday calculator

[Prium]

Hi,
I am hopeless at remembering birthdays tbh - so rather than rely on family to remind me, I decided to make a spreadsheet that shows: D.O.B, current age (in years, months, days), and number of days remaining until next birthday.

Please see attached - I can't figure out why the current age calculation is a month out. e.g 'Sebastian' was born on 16 Nov 2008, which makes him 3 months and 11 days old - but '=TODAY()-C16' yields "00 Years 4 Month(s) 12 Days"

Also, 'Leah' has just her birthday - but now where it is supposed to give 'days until next birthday' it gives an error with the formula: '=DATEDIF(TODAY(),EDATE(C4,(YEAR(NOW())-YEAR(C4))*12),"d")'