Glow and my period!

Hi girls! I have a question. So I track my periods here and also I just started taking birth control for the first time. The thing is I get my periods every 18-19 regularly but the birth control pill I'm taking won't let me have a period but every three months. How do I let this know to glow app or how do I do it so the next few weeks I don't get the "I'm possibly pregnant" if you girls understand what I mean.

So I'm hoping someone can help me with this and TYSM in advance! 💕