Your ACT composite of 20 is slightly below the national average of about 21.1, but it’s right around the average–or even above it–in many individual states. (See http://www.act.org/newsroom/data/2012/states.html ) Your essay score of 8 is roughly a median score as well.
So, yes, you can certainly be admitted to college with this score.. However, I don’t know where you’re aiming. If the answer is Harvard or Yale, then probably not. But there are many good institutions that will welcome you with this score, assuming that your GPA is also within the acceptable range as well. If you’re not sure which ones might interest you, try College Confidential’s “Supermatch” at http://www.collegeconfidential.com/college_search/ .
You can enter all your preferences for size, location, major, etc. Under the heading near the top that says, “My scores,” select 20 and also “Must Have.” When you check your results list, you should find colleges that accept students with ACT scores like yours and that also meet all or many of your other preferences.
Although you will certainly have options with a 20 on the ACT, you might want to try the test one more time in the fall. The practice you’ve had by taking it once may mean that you do better the second time around. This could mean more college choices for you and possibly more scholarship offers, too.