can i take a pregnancy test now? help!!

i am supposed to start my period today but it hasnt come yet and i usually get really bad cramps a couple days before and my boobs usualy get sore but i havnt felt until today and its not as bad as it normally is. my so came in me the day after glow told me i was supposed to ovulate which was the 18th. if u took a preg test rn would it be accurate