Resident alien for tax purposes? filling for 5th year on F1

entered the US as an F1 student on Aug 2014, graduated in may 2018. now I'm working on OPT. When I try to use glacier to file my 2018 taxes, it tells me I'm a resident for tax purposes for 2018. Wouldn't 2018 be included in the 5 years as an exempt individual? I get that for my 2019 taxes i'm a resident but what about 2018/?