First thing you should do is build your body up to being able to run 1.5 miles straight. Don't worry about time just worry about completing the distance without stopping. As you are able to complete that distance consistently, then you should start focusing on pace. 1.5 miles in about 10 mins is about 6 minute mile pace so you would want to aim between 3 minutes to 3 minutes 30 seconds for each 800m(splits would be 3.30, 7, 10.30). It's possible to do by May but you are going to have to be committed. Also, I hope this is being done on a track, ideally synthetic.