Surfing Waves

So I'm a newbie at surfing and I'm trying to move to bigger waves...like 3-5 ft, and these waves break pretty fast. The problem I have is that when I drop into a wave the actual drop is higher and steeper than before and the tip of my board drops down and goes in the water and pretty much wipes me out. I tried standing up faster and kinda pushing down the back of my board but I still have the same problem. I have a 6' 9'' shortboard (well its not really short) and the tip is even raised a bit. But once the tip goes a few inches under water the whole board flips foward.

What am I doing wrong?

It's called pearling. Others will give more advice, but here is two of the basic ones:

1) A 6'8" board does not fit vertically in a 5ft wave, hence you pearl. So to solve it stop paddling straight to shore, paddle at an angle towards the wave face.

2) Part of it is that you are not catching the wave early enough, seems that the wave is already curling when you stand up. You are either not judging the wave right or you are not paddling hard enough.

Others will chime in, all advice will help, it could be one thing or another, so try it all until you figure it out

Good advice from the math teach.
To ad to that, I'll bet you're surfing at a beach break. If it's possible drive to a more mellow break until you build up enough strength to paddle in faster. I learned at a beach break. The good thing is once you get it down you can surf anywhere. The bad thing is it's a lot harder for a beginner so just surf and have fun.

Yea I surf at a beach break and I just got a 4/3 mm fullsuit and that doesn't help with the paddling at all. I think I'm gonna try to find a different spot.

As far as paddling at an angle, how much of an angle should it be? I know it's different for all the waves but I seem to get knocked over on my side.

paddling at an angle takes osme practise as you quite rightly say that eah wave is different. However after enough practise you start to find your rythm,form,sweet spot etc etc... In general though the angle shouldnt be extreme just enough so that you can make the bottom without perling. However some waves do not allow this so you may end up pulling down verticle and making a very commited bottom turn. Practise makes perfect. Finding an easier going break is certaintly a benefit.

Its funny but i learnt in a fast beach break and when i started going to a few slower beaches i hard a real hard time working out that i had time to think

Same here, I learned in IB but when I started surfing SMH and Sunset I would lean forward expecting a burst of speed but I would end up falling off instead, took some getting used to