Hello and thanks for your post.
The application process is truly holistic, and committees will look at your stats (GPA and GMAT), work experience, and extracurriculars.
Your GPA is really strong, so that is a good start. Your GMAT is also excellent. In terms of work experience however, the average years of work experience is closer to 5, so if you choose to apply with fewer years, make sure you demonstrate why now is the time. And because of your lighter experience, it’s even more important to show you have made an impact and demonstrated leadership there. Ideally this will be supported by strong recommendation letters as well. It will also be important to explain why you want your MBA, and to also illustrate the skills you already have which are transferable. Be sure your story makes sense, and is realistic and specific. Regarding extracurriculars, make sure to really emphasize your leadership roles you have taken on.
Though your work experience is a bit light, your largest obstacle, like you mentioned, is simply applying in Round 3, where there are many fewer spots. And if you are not admitted in Round 3 but choose to apply to the same school in Round 1, you will really have to show improvement, and this is not easy to do given that it is only 6+ months away. So I suggest you apply to a range of schools now, including reach, target and safety. And because it may be hard to show improvement in just 6 months, I would save a few of your top choices for Round 1 next year, and not apply to them right now in Round 3.
Good luck!