Weird notification from glow🤔

So I’m 6 weeks and 6 days, I turn 7 weeks pregnant tomorrow. My dates have been confirmed through the doctor and the date is correct on Glow. So on my log it says I’m 6 weeks 6 days pregnant, but glow sent me a notification that said “congratulations you’re 6 weeks pregnant “ as if i just turned 6 weeks today instead of 6 weeks 6 days, turning 7 weeks tomorrow. I’m just confused, do they measure weeks by completing that week? It just threw me off because I would expect this notification 6 days ago, or tomorrow once turning 6 weeks. Not that big of a deal obviously, I was just curious.