Glows telling me to test! Advice needed!

Kyrsten • 24, married 8/2/2014, Gracelynn Rae born 11/27/2015, baby #2 due 10/25/2017 ❤
My periods due in 3 days and glow is telling me to take a pregnancy test! I wanna cave but I promised myself I wouldn't test until after AF's arrival date which is October 6th! 
​What are my chances of testing now and receiving a positive? Any advice ladies?