I was in the US Army from 1984 to 1991 (got out when the stop-loss ended, just after the first Gulf War.) I was in the band - the last five years, stationed in Belgium with an international military jazz band. There was no diagnosis for AS back then - but it was obvious to everyone that my wiring was a bit different.
First of all, you have to get through basic training - I think it's probably still about 8 weeks long. You have to learn to make eye contact & stand perfectly still for long periods of time. There is an extreme emphasis on physical tasks - lots of push-ups, sit-ups & especially, RUNNING. On the plus side, EVERY situation has a protocol - the rules are very easy to learn (they are almost always written down, where you can study them.) You usually get one chance to screw up in any given situation (more, if you can demonstrate that you are trying.) Others have to ask your permission before they can touch you (although they can & will get VERY CLOSE - in your face.)
Once basic is over, it gets much easier. AIT (Advanced Individual Training) - the next part of your initial training, where you will learn your specialty - can be quite relaxed (comparatively.) There is an emphasis on inspections (everything from the uniform you are wearing, to the clothes hanging in your closet, to the floor of your room) and your proficiency at doing your job. It's a total meritocracy.
Once you actually arrive at your post, it's a job like any other. Some people won't get along with you & others will.
The greatest thing about the military, is that it's all about the rules. Learn the rules (as I said, they are written down for you), understand the rules (you can ask your supervisor), follow the rules & you will do well as an enlisted person.
I often think I should have stayed in for 13 more years - life in the military certainly appealed to me. But then I think about having to find a job at the age of 46, with no civilian contacts & no real social skills... Well, suffice to say that I needed those 13 years to get where I am today in the civilian world (stable job, in a non-music field.)