Birthday party

So my nephews birthday party is this weekend while they planned for a month straight my brothers GF said they wanted to PJ mask because that’s what my nephew wants so last night I create an event on Facebook for my sons 2nd birthday part and I put batman as the theme. (My sons birthday isn’t until January) this morning my brothers GF posts on Facebook that she is now changing the birthday this weekend to a Batman theme. Is it wrong for me to be ticked off about it? Picture of my son just cause he is so cute 😍