Questions about enlisting into the Army, can you offer advice?

Mainly I want to make sure my recruiter is not pulling one on me.

From the sounds of it, as long as my score is high enough and there are openings for the specific job I’m interested in I will get it.

He told me how it works now is that they reserve that spot if there is one for 7 days. I then have that time frame to say yes or no.Then go to MEPS review my job title, years doing it, etc….Then sign it if I want that job and swear in.

Is that how it usually works? Is there a possibility that they can switch me or some how put me to a different job or once I do that it is locked in?

I was told to be careful since recruiters just want you to join, so I am asking for extra reference.

Also other advice or general knowledge I should know before actually joining completely.