Is it really hard to loose weight?

Is it really hard to loose weight? I keep asking this question to myself. As I grow older, I'm having a hard time in loosing weight. I gained a lot after the holidays. Well of course during Christmas season party is everywhere.And it's so hard to say NO to my friends. Now I am really having hard time in trimming down. Seems so hard for me to loose compare to other people. My sister is also overweight but she was able to drop 20lbs. in 2 months time. I hope I can drop some pounds also soon....