Hello,
It is normal, if you are a thin person, to be able to palpate your pulse with deep palpation of your abdomen. If you don't have any family history of aneurysms and don't have a connective tissue disorder like ehler-danlos or Marfans, it is very unlikely to have an aneurysm at such a young age. We always recommend discussing these things with your doctor if you are concerned, but, in general, what you are describing is most likely normal.
Yes is normal to feel ur heart beat in your stomach..