<p>You have all next fall for a third. D took Bio M fall sophomore year, Chem spring junior year, and math I and II fall senior year.</p>
<p>I would think long and hard about what excuse you would have for not doing the third. Is it really worth the chance that Harvard will not think your excuse is adequate. You have next october, november, december and maybe even january to produce the third score.</p>
<p>My son, 5 years ago, took chem at the end of his sophomore year right after taking honor chem (not AP) and scored a 730. Therefore, you might even be ready this year. But there is nothing wrong with spreading things out.</p>