Do I choose a metal filling or a composite resin filling?

Ask your dentist. Deciding which type of filling to use is best made by the patient and dentist, taking into account the size and location of the cavity, patient history, cosmetic concerns, insurance coverage and cost.
Your choice. I have not used amalgam in my office in over 15 years. Composite more technically sensitive. Be sure your dentist is meticulous in restoring your teeth.