An important thing to consider when running your own office is that you will not just be doing the counselling work, but also marketing, accounting, employee management (if you have any), etc. You will be running a small business.
You might consider working for another counselor when you graduate from school just to get a feel for how the business works. There are also resource organizations, such as the Chamber of Commerce (for all small businesses) to subject-specific organizations in the healthcare and counseling fields. These are good places to meet people who have faced similar practice-management problems, but of course are a bit more difficult to navigate when you are on the spectrum. You should also consider developing a relationship with both an accountant and an attorney upon starting your own practice. You don't have to use their services constantly (and probably can't afford to as a new business owner) but having a little advice on startup and a person to call in emergencies can be valuable.
Good luck.