Where do I START FIRST

Hey there, welcome! I am also 5'3" and started on MFP around 180 back in January. I agree with the other posters, the most important thing is to log all of your food/drinks and figure out what you are consuming and then trying to stay at your daily calorie goal. I have a food scale that I rely on to help me find the correct portion size of what I eat. As for exercise, I started the Couch 2 5K running app and that was great for me to have 3 structured cardio workouts per week. I also do Hot Yoga 2-3 times per week. Find what you like to do and it will be easier to commit! Add me as a friend if you'd like!

Log everything that goes into your mouth. I can't stress that enough. I was so shocked at my calorie consumption when I started. I had all kinds of excuses as to why I couldn't lose, but it turns out I was consuming waaaay to much. Also weight training is essential. Start slow and work up. It isn't a race, but a lifestyle change. Don't overdo or you will set yourself up for burning out or injury. Cardio is just as important. I started with walking and have worked up from there.

Start here:
http://community.myfitnesspal.com/en/discussion/1080242/a-guide-to-get-you-started-on-your-path-to-sexypants

http://community.myfitnesspal.com/en/discussion/1235566/so-youre-new-here

These are good, too:
http://community.myfitnesspal.com/en/discussion/1161603/so-you-want-a-nice-stomach

http://community.myfitnesspal.com/en/discussion/1217573/so-you-want-to-start-running

And these two if you want/need to log your food more accurately:
http://community.myfitnesspal.com/en/discussion/1290491/how-and-why-to-use-a-digital-food-scale

http://community.myfitnesspal.com/en/discussion/1234699/logging-accurately-step-by-step-guide

These are good posts, too:
http://community.myfitnesspal.com/en/discussion/1343719/get-rich-quick

http://community.myfitnesspal.com/en/discussion/1346163/change-your-mindset