I'm confused. Fencepost problems can be troublesome, but in this case the first event is in a different category.
4/14/2012 Wedding
4/14/2013 First Anniversary
4/14/2014 Second Anniversary
4/14/2015 Third Anniversary
4/14/2016 Fourth Anniversary
4/14/2017 Fifth Anniversary
4/14/2018 Sixth Anniversary
4/14/2019 Seventh Anniversary
4/13/2020 Eighth Anniversary
4/14/2021 Ninth Anniversary
4/14/2022 Tenth Anniversary