The system is simple and, thus far, largely unavoidable. When a user attempts to make a post, Craigslist asks for verification with a viable phone number. It then automatically calls the number and issues a verification code which must be re-entered for the post to go live.
For the purposes of the IRA distributions, a first-time home buyer is anyone who hasn't owned a present interest in a main home for the previous two years. For example, if your parents have promised to leave you their home in their will, that isn't a present interest in the home, so you still qualify.
According to the 2009 American Housing Data survey, the average age of first-time home buyers was 34, while a report put out in 2012 by the National Association of Realtors estimates the average age for first-time home buyers at 31.