Hi @Jennifer54, welcome!
I am sure you must be anxious about your daughter, I would be too.
Of course, stress can also cause glucose spikes with normals. If she is subject to anxiety attacks, it is possible that stress is what caused her to shoot up, at the same time as her gulcose was going up with the tacos. Normals can get very high glucose rises: I read somewhere of a nomal eating a large burger and fries while wearing a CGM and going up higher than 180.
So it may not be D. But with a sign like this, I would definitely take her to the doctor right away.
Since she wears a Dexcom - does she spike for every meal? What type of meal does she spike on?
I know it's hard not to worry - but there may be more than one possibility - so best not to worry (and not to worry her) unduly. Yet it would be best to take her to the doctor swiftly.
Looking forward to reading more from you. I am hoping that, in a few days, you will be back here, writing "it was nothing"!