I feel guilty i know the gender.

So we have a gender reveal the day after Christmas, and only my mum was meant to find out today... but im so impatient and so is mum and my partner thought... stuff it lets find out... TURNS OUT IM HAVING A BOY! glad I can tell SOMEONE cause now I have a gender reveal i have to throw and and well my mums throwing it and now she feels like its a waste of alot of money cause "we know" and shit I feel guilty as now!! I have to fake excitement on the day!