I have some questions about me playing football (soccer) please help me or give some advice?

Hi. Im a 13 year old american boy who loves the sport soccer. But the problem is, i have barely ever played before. I want to start playing this year in 8th grade. But i lack a lot of experience. I have been to one soccer camp in 2nd grade and i rarely kick the ball around with my friends. So clearly im not even close to ok at the sport. But i do have some advantages in my physical and mental attributes. First thing that could help me is that i know almost everything about the sport of a soccer and i could answer most questions any1 could ask me about the sport. Also i am fast, i have great reflexes, i can jump high, i am well conditioned, and i would say im in th 70th percentile for strength. My thoughts are just to go out for goalkeeper. Please help and give me advice.