Period is suppose to start today

So my period it's suppose to start today. Lately been getting it a day early or usually early in the morning. It's only 11:30 where I'm at but let's say I'm tempted to go to the store and but a test but I told myself I wouldn't until I'm at least 2 weeks late. With my son I didn't test till 6 7 weeks than went to a doctor to confirm at 8 weeks. Ahhhh! I hate this part.