how do you keep from nose diving while surfing

Stand closer to the tail. The reason you nose dive is because most of your weight is closer to the nose of the surfboard which makes the surfboard tip downward. But be careful, if you put too much weight on the tail then you will lift the nose out of the water completely and end up losing the momentum of the wave.

wear a nose protector

l agree with Kaye L

when your dropping down, put your weight towards the back of the board. You have to lean back a little bit.

While you take off angle your board away from the breaking part of the wave which will help you not pearl because the drop wo not be so steep.

Good Luck,
The Surfboard Man
http://thesurfboardman.com/

Take off on a diagonal, paddling across the face of the breaking wave, in the direction that it is breaking. Do not paddle straight for the beach, you will pearl every time.Get up faster, and keep your weight centered, not too far back, you will stall.

l agree with the first answer, but also your rocker may not be suitable for you.. you prob need a medium rocker

add more info. are you on a short board? long board?

Well it depends on what kind of board are you riding?
If its a shortboard get on the line earlier
If its a longboard as soon as you catch the wave pop up and move to the back of the board then come forward towards the very end on the drop-on
kinda of complicated but if it doesnt work try arcing your back when paddling and then pop up earlier