Regarding GMAT eligibility

Good question -- that really depends which programs you're applying to. Most top MBA programs traditionally have an expectation of three or more years of full-time professional experience at matriculation, and if you're an unpaid intern, that may or may not count towards this expectation. In the last few years, however, many top schools have been more open-minded about age and experience.

Since your question is pretty general, your first task would be to identify the schools you most want to go to and your post-MBA goals, and then review the average years of work experience of each school's incoming class. That would give you the most accurate information about where you stand in comparison to your potential classmates.

A high GMAT is a definite asset, but MBA admissions is a holistic process, and all of your background components will be taken into consideration. It's great that you're getting the GMAT out of the way soon, but you might want to delay your applications until 2019 if the schools you're applying to do not have a history of taking applicants with your level of full-time experience.

Good luck!
Margaret Strother