You should practice controlling the ball and passing at first. If you haven't ever played it before, I doubt that you'll be able to hold on to the ball for over 2 seconds despite your fitness. I'd also suggest you get somebody to pass to you, you to pass back to them while moving around while also getting another person to try and cut out your passes and try to tackle you.
Just go there and play centre midfield. Practice passing, tackling, control and marking. In all honesty if you've never played before then you really need to join a team or training session to learn the basics. You'll be pretty useless if all you do is get the ball and pass to the side or back while also not being able to cut out passes or tackle.
You could try play soccer nobody can tell you that you can't do it, soccer is 90 per cent talent and 10 per cent training, you should however start training by yourself first to see if you got it, practice shooting accurately and sending high passes, the trickiest is dribbling which means controlling the ball while running, here the talent can show itself, if you are good at dribbling then you can play soccer, don't be put down if you couldn't handle it right away though cause it's a brain process, you should allow your body and brain some time to reprogram and that is through practicing it again and again
So I want to join my high schools soccer team in the spring but I don't think I will be able to do it. I played soccer once when I was a lot younger and now I'm a freshman at a new high school (a good one for sports) and I don't know if I would make the team or humiliate myself trying. I do cross country so the running I would be able to handle. I just don't know if it would be good to try it? I already missed the Fall season of soccer that's offered in other places other than my school...should I try indoor soccer somewhere or just not try at all?