Surf some inside sets.. Get a feel of the waves crashing into your face. Get the feel of getting up on the board and cruizing and position. Go on a smaller day or just surf the inside. My first day out when I was little was on a short board in some pretty big waves 3-6ft maybe. when I was younger. I didnt know how to duck dive, I just ditched the board and went under. Nothing happened to me but i was stoked to get outa there! And ****ting my pants on the paddle in cuz i didnt know how to ride waves!!! Just gotta become nature to it. TIME!!! thats it!!!