Late period & confused by dates!!

Jess

Just wondering if anyone has any idea because I am clueless! I had my last period on the 17th jan & I still havnt come on yet & I worked it out that I was 5 days late but numerous apps have said I’m 7 days late?? I thought I would come on round the same time this month but still no sign of AF!! Is it to early to take a test??