How long did the sensation of heart beat going fast last? Does it feel regular or irregular? You may try to use a BP machine or an android phone app to measure your pulse rate during the symptom. If is it less than 110 bpm, it is usually not abnormal heart rhythm based on my experience.
Other possibilities including endocrine cause will need to be explored. Abdominal aneurysm, although possible, is unlikely at your age group.
If the symptom lasts more than 30 minutes, you can try to get an ECG during the attack at the nearest clinic or emergency department. If it is shorter but happens fairly frequently (daily or every few days), an event recorder or Holter may be useful.
If you are worried, you should consult a doctor who can advise what to do next. Many of the abnormal heart rhythm at your age group is curable. In some cases, no further treatment is required.