I scored a 28 on the ACT first time. Is that good?

Don't listen to Zara because the ACT test is out of 36 and not 31/32... But I am not quite familiar with the colleges that you listed but if you want to go to a more presitigious college, retaking the exam is very necessary. Straight A's, internships a relatively high ACT score (higher than 28) will get you into good schools but not the most elite. If you are looking at Harvard/Yale/Stanford/MIT etc. you'll need to do something that will separate you from the rest of the herd; good scores won't just get you in.