At 20 years of age, Bouchard is the youngest Grand Slam finalist since 19 year old Wozniacki at the 2009 US Open.
As mentioned in another thread, Azarenka was the last first time GS finalist to win a Slam (2012 Australian Open). Since then, there has been a succession of 6 first time Slam finalists, none of whom succeeded or have (as yet) made another Slam final: Errani (2012 French Open), Radwanska (2012 Wimbledon), Lisicki (2013 Wimbledon), Cibulkova (2014 Australian Open), Halep (2014 French Open) and Bouchard (2014 Wimbledon).