Should i move the date of my bday party? or is it too inconvenient?

Basically was gonna ahve my party at thorpe park onsaturday 9th july but my teachers at school are going on strike on thursday 30th june (in 2 days time) i think it will b quieter on thurdday with less queues but is it too short notice to tell them 2 days before??? PLZ ANSWER SENSIBLY AND ASAP!!!!!!!!!!!!!