Currently 2 days late

So I'm wondering when it's safe to say that I've missed my period. I'm currently on cycle day 29 and I usually start before cycle day 30. I'm just so confused cause this app is usually right for me. I currently don't track ovulation so I don't know when my ovulation day was. Last month I started one day late which was on cycle day 27. Any advice is greatly appreciated and thanks in advance.