Yes, I think my poor handling often causes the stress. Letting her meet the other dogs probably wouldn't help in class, because she's already met them. My teacher advised me to be sure she's holding her start-line stay. I didn't notice that sometimes her little rear was lifting up a bit. Also she suggested to do just one jump and then reward her, as a little warmup. At the last class, she zoomed because I hesitated a little while she was doing the weaves. I wasn't sure where the next obstacle was. Molly noticed that and missed a pole. When I took her back to start the weaves again, she took off.I've heard dogs find zooming as a way to get out of the moment, and it's most common when they're stressed out. My dog used to have the zoomies at agility a lot, but I gave him some time to individually meet each dog and play with them which seemed to help ease up the stress. Since then, he doesn't seem to have any more stress zoomies and only the occasionally, "Let's go crazy!" terrier zoomies!
I suppose there's no one magic solution.