You may or may not be privileged to select your own interview date. Smile about it. :) You have made it this far. Stay optimistic.
Some countries only have one U.S. Embassy (e.g., Indonesia, Mexico, Philippines) while others have more (e.g., Canada, Turkey, China). Each U.S. Embassy in different countries has its own procedure and requisites when it comes to the medical exam, scheduling the interview, and actual interview.
If you get to choose the schedule you really want, that's good news. You could follow your plans. If you don't have the chance to pick your preferred interview date, just enjoy the preparation period. It's not only the destination that matters but also the road towards it.
See the contact details of the closest U.S. Embassy for your location to find out how it operates.
Secure all requirements first before agreeing to an interview date. Although rescheduling an interview is possible, it may cause unwanted delays and complications. Cliché but observe caution. It may be an uphill climb at this point but you are about to reach the summit.