No fast tracks for obgyn. You must go through it all. However, given your age the odds of you deciding to do something else are through the roof. Even those in med school change what they want to be. So keep your dream but be open to other experiences, as you will have them all. Also, you might want to speak with an obgyn about what it is really like. It's not all helping women have babies. You have time though so no rush.
What will help you is to enjoy your life and make As in those classes that count toward your college degree. All college level coursework counts, even that taken while in highschool. Especially make As in those college sciences!! That said, dont freak out if you make a few Bs along the way (Fs are another story, but still not worth freaking out over). Often people get the idea that you can only be a dr with straight As, but by the same token a straight B avg won't get you there either.
Good luck
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