My late periods strike again lol

Ari

My period have always been on and off sometimes I get it twice a month and sometimes none at all. This is the first time in awhile my periods been extremely late, according to this app from when it said my period was expected, I’m 16 days late. Should I take a test just for the state of mind or could it be a month I just don’t have it (it’s happened before for me). Thanks in advance for the help!