Just getting started...new mind set.

I am just getting started on MFP. Last year I lost 40lbs on Atkins...WONDERFUL! But here I am, gained the forty back plus some...I am not really feeling up for this....but Lord knows I need to @ 275lbs. I need a new mind set....gotta get weight loss in my head!! I have not attempted a reduced calorie diet....usually do low carb. Also, I am 60 years old I have heard it is harder to lose weight on this side of "the hill" LOL But, I am going to do this!!!!