Why did my boyfriend put my birthday for his birthday on snap?

So I am not allowed to have snap but my boyfriend is. My friend is friends with him, and she noticed that on Snapchat his birthday was the same as mine. I told her that that wasn’t his birthday, so we were confused as to why he put it as his even though it’s mine. I don’t think it’s suspicious I’m just wondering why he did this. Can’t really ask him bc he’d know I’m stalking his social media lmaooo.
Why did my boyfriend put my birthday for his birthday on snap?
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