As I understand it, you must be 13 to use this site, so your birthday would verify your age.....Just my guess.
Yeah, like everyone else is saying, you must be at least 13 to create a Blurtit account and ask/answer questions. Some reasons as to why the site was made like this could be:
- To block off inappropriate content to children younger than 13
- To prevent these younger children from spamming/trolling the site and its users
- Keep the maturity level and its seriousness high, as children younger than 13 most likely aren't mature enough to use this site
There's probably more but I can't think of any other reasons.