In order to use the local calendar for birthdays/anniversaries and calculate how old someone gets it would be nice to be able to set the start date of the recurring yearly event to the birthday date. Unfortunately we can’t go prior to 1970 in the date picker.
I have a workaround where I add the year as the first digits in the description and then calculate the age for the notification. Using the event start date seems much more elegant, would simplify things and leave the description free for other things.