Your first case will always be the best experience. Here are few tips to overcome the fear.
Understand the procedure, practice all difficult situations in your model itself.
Take deep breath and never hesitate to ask help form seniors or staffs.
Dont fear for bleeding during extractions. If you feel unusal please inform your staff.
Dont leave the procure of half way. When someone guides you by doing the procedures learn from them.
College is the only place where you can learn by doing mistakes. Dont fear for mistakes.