Hearing you @Teej ......
Break it down into baby steps Hon.
The thing won’t go straight to the presentation. There will be some sort of intro. That gives you extra time.
Dont worry about the crying in the moment. Throw a make-up bag into the car with you and drive there. See how you are feeling by then and if you are up to getting out of the car.
If you are, and you have stopped crying - being in a different place and time by then - tidy up your face and are out.
If you’re not up for it, sit in the car until / maybe / if / you are ..... you have time.
You have the option of stepping in at the end to view the presentation as it is laid out, letting your son know, or not, whether you have been there the whole time.
You have choices, and you can always turn around and drive home again at any point.
💜💐