No, @OG, I think you have a very strong shot at Stanford and MIT. Just elaborate on why math means a lot to you, and elaborate on your other activities. The fact that you missed MOSP by 1 point is unfortunate, but don’t try to mention that in your application, or they may think that you are making excuses.
Anyhow, you are in a great position, and with a great essay you will make it.