TLDR to my yapping: neither originally knew who the other was until their feelings were (mostly) told to the other, so revealing the secret now would stunt or ruin their relationship.
I feel like a lot of people are forgetting their relationship at their job practically started with both of them telling each other their feelings for the other.
Both of them didn't really realize who each other was and while our MC is not the brightest tool in the shed i dont doubt that once he figures out her secret, he'll realize everything else.
I think if this was the other way around i believe he would do the same thing she's doing and be just as embarrassed, it would probably be worse if either admitted as soon as they knew because it would thrust them both into an uncomfortable relationship of barely knowing one another yet knowing they both have feelings for the other which, more likely then not, will end up hurting their relationship more then helping it (realistically speaking.)
Of course it will be horrible to keep this up forever and morally it would be best to reveal it the second she knew, but then their feelings are known and they'll have to talk about it, not to mention they're teenagers and teenagers will prioritize their feelings more then doing the logically best thing to do
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