had you decided about pursuing medical science after completion of your +2 back in nepal, probably you would be doing internship at this time and in a year or two you would be here applying colleges/hospitals for residency.  the big advantage of foreign MBBS is that they can complete education in shorter period with comparatively low cost.  however, in usa, the cost is very very high and getting into medical school is really tough and takes a long time ( 6 years after undergrad) to complete.  However, you will get MD unlike in nepal or india, where you get MBBS.  anyways, you can try if you have very good academic records and MCAT score.  it does nt hurt to try.  good luck.