Legal Question in Criminal Law in Texas

Actually, yes you can avoid "state jail", because Aggravated Robbery is a first degree felony, not a state jail felony, so a state jail sentence is not in the cards no matter what. Can you avoid having to serve prison time? Well, there are a lot of different plea and punishment options available, and it's possible that you could get anything from deferred adjudication probation to a life sentence. I rather doubt you'll get a life sentence, since you didn't actually have a weapon and walked away without doing anything else to threaten or harm the clerk, but there are a lot of other factors that would go into determining what will actually happen in your specific case--everything from your prior record to whether there was actually some kind of reason why you did this to how seriously you frightened the clerk (and what his or her feelings are about the whole thing) to what kind of judge or jury you get to what the policies of the DA's Office are. I'd talk to your attorney pretty extensively about what your options are on taking the State's offer versus going to trial, since your attorney will have access to all the facts of your case and will hopefully know enough about the local court's and prosecutors to be able to give you some idea what's likely to happen if you do go to trial. That's just not something anyone on here can do--we don't know nearly enough about the specifics of your situation. Good luck.