alt Hacker NewsThe most relevant question to answer for your jurisdiction is "What is the penalty for lying?"
If none, you were born on March 5, 1957.
(Note on evaluating this: there are some circumstances where the penalty changes later. I know one person who's Global Access paperwork was delayed because they lied to their airline's frequent flyer program about their age. But that was the whole consequence: a need to update their data with the airline).
Whenever Steam's web site asked me for my date of birth before allowing me to view a game trailer, I would punch in January 1, over 10 years after my actual date of birth (still well within grown-ass man territory because I'm geriatric in gamer years). Because they don't fucking need to know exactly when I was born. Only that I'm old enough.