I hope this is the beginning of a great bowhunting career for you. I, and I stress the I, would recommend A/C/C arrows or carbons. They are more expensive, but they are also more durable, straighter, lighter (oh no there is a whole new argument). The length that you will need is best done by drawing the bow back with a full length arrow on it and having someone mark it about 1" in front of your rest. I am assuming that you are having a proshop prepare your arrows for you. If so, then they will take care of all of that. If you have your own cutter, than measure all the following arrows off of the first to ensure that they are all the same length. You will probably hear arguments for all types of arrows and some will say the heavier the better. They aren't wrong either, so weigh your options carefully for yourself before you decide.