I started at a 155 diagnostic four weeks ago, and was considering June but I think I'm going to commit to August. I have averaged low 160s for three practice tests, so I don't think I can hit goal (170) by June at this current pace. To answer your question, I don't know how much law schools care about repeat attempts but in my opinion it's better to take the test once and get the score you want and not rely on repeat attempts.