My daughter today was violently sick 4 12 hrs throwing up. she is 20 yrs. she fine now and eating normally. was it food poisoning?

Probably: Or some other likely viral infection. Often if symptoms have resolved is fairly academic distinguishing between food poisoning and gastroenteritis (tummy bug). May if recurring symptoms need to consider other possibilities such as urinary tract or other infection or migraine in which case a doctor assessment would be recommended. But if all settled for now can wait and see

Seems likely: Did she eat any culprit foods like reheated rice? Often food poisoning results in diarrhoea as well as vomiting but occasionally it will be one or the other. If she is well without ongoing fever or abdominal pain then there is not much to worry about. If she works in an industry involving food preparation she should not work for 48 hours.