^^
"Early" means get them by May and wear them and the low quarters a few times a week before R-Day. The low quarters are harder to break in and I'd recommend a soft insert. You will receive a "boot letter" which will tell you the authorized styles and manufacturers for the boots and low quarters. Only bring one pair of the authorized style for each. You can use different boots during the academic year so wait till after the summer to purchase them. Other than that, go find a hilly four mile loop to run and get out three to four times a week to run. Do push-ups, sit-ups and pull-ups three to four times a week. You will take a screening APFT in the first few days and for 2017, in the first hour, they were required to do pull-ups (in the rain) for screening purposes. I'd guess you'd want to look good for both. The standards for the APFT for each age group are readily found on the internet, and you will want to aim for a score in the top decile. My 2017's roommate failed and it made life fairly miserable through the fall semester, with major restrictions on activities, passes, etc. So don't be 'that cadet'. Best of luck - don't worrry about equipment/boots yet - you are better off building the best fitness base you can before June.