Do I need to bank blood before having surgery?

No. You do not need to bank blood before surgery but if you are medically able to donate blood shortly before surgery, that is better. If you end up needing blood during or after surgery, you can be sure that the blood transfusion you get is safe since it's your own. If you don't need it, then you get to help someone else who needed blood.
Maybe? What type of surgery are you going to have.? Your surgeon will know if you need to bank blood and i suspect if he has not told you do do so you do not need to. Ask him/her.