Around year 2000 median age was 4 years, 2001-2009 was 8-9 years and since 2008 median age has been 9-14 years with the majority more than 10 years.
I am not sure if the last chapters of "The hard thing about hard things" or "Venture Deals" had more details.
So you can expect Series A with fresh funds and money (10 years runtime left).
Around year 2000 median age was 4 years, 2001-2009 was 8-9 years and since 2008 median age has been 9-14 years with the majority more than 10 years.