<p>It’s actually fairly common among MIT students to be in that situation (although many people did get there by skipping a grade or two). My birthday is in February, and I went from being about the middle of my year in high school to being one of the older students in my MIT class.</p>
<p>I don’t have any information on whether it’s actually considered by admissions (I doubt it is), but it is certainly a common thing at MIT.</p>