First Day on MFP

I'm a 5'5" female and going to be 50 in a couple of weeks. I'm trying MFP because I'm sick and tired of being sick and tired. I'm currently at 318, down from 326. (It might even be 333, I was too afraid to get back on the scale to see if I was reading the number correctly.) As you can imagine, I have lots of health issues. I'm losing weight because I think I may need surgery in 2018 and I know how dangerous surgery can be if I'm this heavy. Also, I recently felt the weight, really really felt the weight for the first time. A few weeks ago, I woke up to run to the bathroom late at night, and I felt I could hardly move my arms and legs. At that moment, I could feel every pound and I finally said to myself, "No. No more!" My goal, 145. I don't have a time frame, but I'd like to be 175 in 2018. I've lost weight before, but I've never been 'serious' about it before. Wish me luck. I sure need it!