Try the board, if you have fun it's the right sie, if not it is the wrong size. More importantly, here is how you want to start, forget anything else:
Get into the water to about your waist, and turn around towards shore. Wait while standing next to your board for a good whitewash that will push you, then throw the board towards shore while you get on the board at the same time. If you did it correctly you'll be on your belly surfing the wave. Try to stand up then get off before it gets too shallow. Do this over and over until you can stand up regularly. Once you can get up more times than not you are ready to get on your board, paddle to a wave, and try by paddling into it.
If you skip this step you will paddle to a wave, turn around, then you will just either miss the wave or not get close to getting up. Practice standing up before you practice how to paddle.
And if you fall, remember to laugh. Mahalo
