Question?

Okay, according to my apps I was supposed to start my period today. My hubby and I have been trying to concieve since December. The app says I ovulated on the 19th, but I'm almost positive I didn't ovulate until the 22nd. If that's the case I would only be 10DPO. SO, if thats the case and my period does not come today, is it still possible for me to get a positive test and maybe I have tested to soon?