Tired of over collecting personal info these days, if you need limit age you can put a claim on the page, or just fill out birth year, why do you need my EXACT birth date to create a username?
> or just fill out birth year, why do you need my EXACT birth date
Because some of us are trying really hard to follow certain regulations. If an auditor saw our age gate and discovered that there were potentially 364 days worth of edge cases, we (our customers) could be in a lot of trouble.
Then put a disclaim page/paragraph saying "you must be fully XX years of age" will do. That's what gmail account does by the way.
By providing such detailed personal info in the past I already been in "a lot of trouble", both bank and credit card were stolen, I'm not alone, in fact too many identify theft these days.