The Common Application has announced that its 2019-20 essay prompts are staying the same as last year's application, which means that if you're a high school Junior, you don't need to wait until the summer to find out what the essay prompts will be for your applications this coming fall. You can read the seven essay prompts here.
Do you need nine months to write your Common app essay? Probably not! The writing is in some ways not the hard part, though. Reflection and brainstorming take time. That's at least half the battle for a successful essay. Take advantage of the lead time for experimentation and do-overs.
Can you get started now if you want to? Yes you can, you eager beaver!
Is there any downside to starting to write your Common App essay now? Not really, but here are some things to take into consideration.
If you'll be applying to colleges that have supplemental essays (i.e. essays specific to that college) as part of their applications, then you might decide to wait until those colleges have released their supplemental essay prompts for 2018-19. Those won't all roll out at the same time, and probably won't until the summer. They'll come out on a slow drip. You probably haven't finalized your college list yet. That's normal.
Once you can see the supplemental essay prompts for all the colleges you'll be applying to, you can see which prompts have topics that overlap, either with each other or with a Common App essay topic. You can mix and match topics in a way that will allow you to get the most mileage out of whatever essays you end up writing, and potentially write fewer essays than you otherwise would have to... if you're strategic about the mixing and matching.
So how do you know which colleges will have supplemental essays? You can see which ones had them in last year's application season in this table. If you zoom in to read the tiny, tiny font (oof!), check out the Supplements > Writing column. If it says "Yes" in that column, then that college had a supplemental essay of some kind in its 2017-18 application (And if the 2017-18 application deadline for that school hasn't passed yet, you can pull up the current applications and check out the supplemental essay questions.)
Can you rely on that information for this coming application season? Probably yes for 90% of them, because schools don't typically change up their applications all that much from one year to the next. But we won't know yet with any certainty until the new table comes out for 2018-19.
If you want to start writing sooner rather than later, you can pick a Common App essay prompt now even before you know what the supplemental topics will be, and then write a another, different Common App essay for a particular college if it turns out that your first Common App essay would work better as a supplemental essay for that college. That's fine too!
Pro tip: You can submit different Common App essays to different colleges. Inline gives you advice for each Common App essay prompt and deconstructs sample essays from the perspective of the admissions officer. That way you can start to think about how they actually use and evaluate application essays. Inline teaches you how to think like an admissions officer as you draft your essays. Inline also shows you how to submit different Common App essays to different colleges, which isn't obvious when you're logged into your Common App account.
Starting to write earlier rather than later also gives you time to try drafting several Common App essay topics, using our Inline do's and don't for each one, and seeing which one feels the most natural and speaks to you the most. Give yourself time to reflect and to brainstorm. Sometimes you don't know which one will end up clicking until you're deep into writing in response to a prompt. ("Essay prompt" gets used interchangeably with "essay question" in the admissions world. They mean the same thing.)
You can download the FREE version of Inline now and get working on the Common Application questions. That information will roll over into your Senior year, no worries. And your Inline tool will roll over into your Senior year as well.
If you need or want help with the Common App essays, the best edition for you is Inline Plus.
And if additionally you need help with the supplemental essays, the best edition for you is Inline Pro.
Everyone starts with the free version, and you can always upgrade later from within the tool as needed.
Or you could run through the sprinklers for now and procrastinate until next fall. We don't recommend that though. :)