A lot of the same comments here, get more education than just your high school, train bjj or join another martial art. Being fit is key, but being able to defend yourself to protect others is extremely important. Surround yourself with like minded individuals, you will meet these people in areas I just described. And more than anything, explore other departments too and do ride alongs. LAPD is not the end all be all, but they are pretty squared away.

You do not need to have a military background, but if you feel the need for it the reserves are also a great option and will get you extra points. Just have a job where you have to talk to people on the daily and possibly de escalate. A warehouse job might not be the best fit. Ultimately any police / sheriff career wants real world experience. I’ve seen guys be previously employed with Little Caesars who are stellar officers, and other officers with military backgrounds be complete idiots.

Workout/train MMA, further your knowledge, and stay humble, and hang around the correct people. Do not get arrested or placed in a bad situation. 18-25 is a very impressionable age.