Lots of wonderful advice here. There's a massive amount of info online.
First, being in high school 1) ask your guidance counselor for advice, what about parents, friends, relatives....2) make sure you end up studying in a place where you are fluent in the language be it English or whatever else. If you're bilingual, even better. The more languages you speak and understand the more of an asset to a University you will be and, of course, benefit patients eventually. 3) make sure you have a CV or resume even though you're in HS still...you have a lot of skills already, (computer, communication skills if you speak other languages, public speaking, leadership skills, etc. I see you volunteer and already have leadership skills...
Here's a link that may help little...Lily says: click me for more info :-)
Info for High Schoolers who want to go to Medical School
Scholarship Info for High School Women-this site has all kinds of categories based on religion, minorities, family, and education level.
Don't forget STEM studies financial aid.
In terms of going abroad...first and foremost....fluency in the native language is half the battle. Sure a foreign country may teach in English in the Universities, but what about living in the society? Funding is another issue.
If you're a female and I know you are, there are women's organizations that will offer scholarships to candidates going into certain fields, plus if you're a minority there might be more available to you.
One thing at a time, worry about undergrad major of biology and or chemistry first...then in your junior year start looking for medical schools always keeping grades in mind and participation in medically oriented clubs/groups.
You're going to meet A LOT of people at University, network and make connections. You're wise to start your game plan now!