While you are a junior! Sunnyslope provides the ACT for free in March/April. As a senior you can still take the ACT again to improve your score. You should take them at the beginning of your senior year. DO NOT PROCRASTINATE.
Well besides the fact that is required at Sunnyslope, its always a great idea to work on your testing skills. Most colleges no longer require the tests, but it CAN HELP you get accepted. Also, you could qualify for scholarships based on your score!
Sometimes colleges will specify that they want an ACT score or an SAT score, but most of the time colleges don't care about which one you have taken, just as long as you have taken one of them.
That is totally up to you! There are differences and similarities between the two tests. Take which ever you feel you will do better on. Some students opt to take both. In your Junior Year, you will take the ACT test during school.
No, community colleges will just take your high school transcripts. Depending on your grades, there may be additional testing,