Welcome!
Getting below 200 by September sounds very possible to me. We're the same height, and I'm about halfway between you and 200 - it took me just under four weeks to get from where you are now to where I am now. So if weight loss is logical, then I'll get to 200 in four weeks and you'll get there in eight.
Unfortunately, weight loss tends not to be quite so logical. But with effort, and exercise and a lovely healthy eating plan, you should be able to drop 24lbs in the 90 or so days between now and September. Keep that as your goal though, even if you decide you can do it faster - if you hit that goal, for example, six weeks in advance, you're going to feel awesomely proud of yourself.
Good luck!