Those are all very valid questions and concerns. There are thousands of different types of abnormalities that could possibly be seen on EKG. Some are of little or no significance, others may possibly be life threatening. Your daughter should seen the heart specialist. Without more information and possibly additional testing, there is no way to accurately answer your questions about your daughter's condition.
Hello. Just a tip before the doctors answer: Try to specify what abnormality/abnormalities the EKG revealed. If you have a print of the EKG, scan and upload it and link it. EKG's are quite visual, and it's amazing what cardiologists can see from an EKG.
Preferably scan it and paste a link. If you can't, try to describe what was wrong. I think the doctors are able to provide a better answer if you do.
Just a final comment: Automatic EKG interpretations are often wrong when stamping the "abnormal EKG". A lot of common and benign conditions may mimic the ones causing "abnormal" EKGs (happened to me a lot of times). But a cardiologist needs to see the EKG to tell you for sure. My cardiologist just laughed when the EKG told I had an infarct at age 24.