Major credit cards are accepted in mostlarge stores or hotels in the larger cities. When you get to school, you may ask where is the best and fastest way to change money. There are ATM machines around, but unless you can read insturctions in Spanish, you'll find it difficult. Public health in Costa Rica compares favorably with that of many developed countries. No shots are necessary to come to the country.
Medical facilities are numerous and dependable.
Many English speaking doctors and dentists practice in San Jose. Unlike other Third World countries, it is safe to drink the water. Costa Rica, in general, is a safe place. Most crime is the petty type. Don't leave valuables or personal documents unattended or in aparked car.