my sister is the ONLY birthday I remember, because we used to celebrate it together due to them being so close together. Never remember anyone else's.
One time I forgot my own.... Actually I didn't forget I just didn't know what the date was so I missed it.
Birthdays stopped being a thing for me about...oh, 7 years ago, I think? They're a social thing, and I don't get out much anymore.
Never really understood why people get upset over not having their birthdays remembered, the only birthdays I tend to remember are the people who have their birthday in the same month as me xD
Never remember anyone else's.