Depends on when your deadlines are. I did mine the October before applying but my deadlines were in February and March. Adjust accordingly and you should be fine.
Well you get 5 times in a year period to take it, and it's good for 5 years most places, so I'd say as soon as you're ready in case you f*** up and wanna take it again.
Speaking of which I'm taking mine tomorrow morning. Ugh.
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Whenever, you just need to take it in time for colleges to be able to receive your scores before the deadline. If you already know your math, it shouldn't take long to prepare for it (the English section is hard enough that the correct preparation is basically to have read a lot over the course of your life; you can probably only marginally increase your score by cramming). I'd recommend taking it over the summer.
-- No I'm not a damn furry. Looney Tunes are different. - Guiga I wanted Sonic/Shadow romance at that time, not sex. - MWE