Visa appointments are limited and visa processing times can vary widely, even within a particular country. The US Department of State maintains a website where you can view estimated wait times by visa type and city:

https://travel.state.gov/content/travel/en/us-visas/visa-information-resources/wait-times.html

Note that wait times may change as your summer program approaches and may be longer during the months of May and June. You are encouraged to plan accordingly.