Here is the Timeline

1982 - Something may or may not have happened with another 2 (or 4) teenagers at a party, she cannot remember who threw the party, where the party was held, who she was with or how she got home. She was drinking and said nothing to anyone.
1983,
1984,
1985,
1986,
1987,
1988,
1989,
1990,
1991,
1992,
1993,
1994,
1995,
1996,
1997,
1998,
1999,
2000,
2001,
2002... She said nothing.
July 25, 2003: President George W. Bush nominated Kavanaugh to the United States Court of Appeals for the D.C Circuit... She said nothing.
2004,
2005... She said nothing.
May 11, 2006: The United States Senate Committee on the Judiciary recommended confirmation. Kavanaugh subsequently confirmed by the United States Senate... She said nothing.
June 1, 2006: Kavanaugh sworn in by Justice Anthony Kennedy... She said nothing.
2007,
2008,
2009,
2010,
2011... She said nothing.
2012... She remembered 'something' happened in 1982, yet doesn't name Kavanaugh, still said nothing to authorities.
2013,
2014,
2015,
2016,
2017 - becomes an anti-trump activist.
2018 - now 36 years later, with Kavanaugh's SCOTUS confirmation looming, she pens an anonymous letter with grave accusations against Kavanaugh regarding foggy circumstance that occurred while they were both minors, then reveals herself and DEMANDS an FBI investigation before testifying.