Leaving baby for the first time

I'm going to see twenty one pilots! Which I'm super excited about ...but super nervous I live with my parents so my son is getting watched by his grandparents I'll be leaving like 5 pm and won't be getting back till like 1am my son who's 15 weeks (will be nearly 5 months) goes to bed at 9 and wakes up at 6 am for a feed them back to sleep till 9am my mum is going to have to do his night routine and I'm scared she won't be able to do it and get him to bed or he'll be confused why I'm not there 😭 any advice ??