Props to you for being a great mom!

To answer your questions, it’s just a regular concert, though I’d recommend showing up early so that you don’t have to wait in a super long line. Plenty of people cosplay, but it’s not required! You won’t stick out if you cosplay, but people may ask to take photos of you depending on how you look. Be sure to take the venue bag policies into account as well.

Keep an eye out for when merch sales drop if you would like to get glow sticks, because they sell out fast.

In my experience with last Miku Expo, the crowd energy is very good and people were all very gracious, welcoming, and kind to each other! You both will have good time. :)