There are so many answers to this question that it would be impossible for me to say for sure. Keep in mind though that it takes healthy couples an average of six months to conceive when they're trying. That's six fertile cycles before they successfully conceive! In fact, it's rare to make that baby on the first cycle, with only 30% of couples finding out their pregnant within the first month of trying.
Before you check in with a doctor, make sure that you're properly charting your cycle so that you know when your fertile days really are. An app isn't a great way to check your fertility since it bases your fertile days on a woman's average cycle - not when you've actually physically ovulated. To know when you've actually ovulated, you'll need to either chart using a Basal Body Temperature thermometer or ovulation tests (which you can find at just about any drug store).
If, after a year of trying you're still coming up with negative tests it's a good idea to let your doctor know so you can get down to the bottom of things.