50 yr old mom of 2 girls 4& 5 need to lose 100lbs

i just heard about this site last thurs nite at TOPS. (Take off Pounds Sensibly). my hubby and i joined again to lose weight. but i really wanted to use this site to log my food.
i gained all this weight since 2009 when i had dbl mastectomy and my dad died within 6mths from lung/bone cancer. very down time for me.
i need to lose this weight to be healthy for me and my little girls we adopted. my son is 31, and i decided to start over again with the girls. they will help keep me active i hope.
rae