CommonApp resets every year on August 1st, at which point the main essay prompts change and many schools change their supplementals. Also, anything you've input will wipe from the site. So you may want to begin to think about what you could write over the summer, even write the framework for very common essays in an external document ( why do you want to study x subject, what was your most significant extracurricular and what did you learn, etc ). But most of your essays should be written next academic year.
As for letters of recommendation, request those ASAP. April/May of Year 12 is when most students request them.
Also make sure you understand the difference between Early Decision, Early Action, and Regular Decision. Early Decision is binding, so if another school gives you better financial aid, you cant simply withdraw from Bowdoin. Bowdoin should be good as they meet full need for internationals with no loans, but make sure to do a Net Price Calculator for them to see what they may expect you to pay. Each school has a different formula to calculate your need, and some are kinder than others. If the Bowdoin NPC gives you a number you cannot afford, you should not do ED there.