Different Apps say AF is coming

Carms💜 • 31💜 11 years married💜Boy Mom💜8,7 & 1 year old💜
So.. Ovia, the app I used before glow, says AF is expected on the 7th. Glow says March 30th and then my friend looked on baby hopes and it said April 3rd. As if I wasn't sure already when to test, now I'm def thrown off😢 
Last period was the 28th of Feb
Then January 23
Then December 15th
So it seems like my cycles have gotten closer since December (got off the pill in August) 
Any suggestions anyone? Ovia says to test on the 30th😏