New to My fitness pal...ready to be the best me :)

Hello,
I'm new to myfitness pal. I joined last week in a desperate attempt to understand my nutrition and how to count calories. Growing up I really never had the worry of how to count calories. I was always the 'under'weight child in my family. I was always small growing up and stayed small through college without much effort. My weight struggle started to become an issue in my late twenties.
I had a baby and was doing pretty good getting back to my pre-pregnancy self and when our son turned three I was dealt a few hurdles to overcome with my health. Just getting through that time was was difficult enough and I started to gain weight and not really caring that much because I was just happy to be alive. I realized how precious life was at the age of 30. Now 40lbs heavier I realize that I need to find balance with food, nutrition, and exercise. I'm very active and love working out. I also teach several aerobics classes at out local fitness center. I'm ready and looking forward to understanding my eating habits and how to better them. Ready to be healthy and fit!