My daughter was adopted when she was 2?

my daughter was adopted by her foster care parents at the age of 2 in ca . when she was born i had a serious drug addiction i tried to get her back before she was adopted but i had waited too late . i have been clean for many years now and i think of her all the time . she is about to be 12 years old and i know there is really nothing i can do till she turns 18 but even than how do i go about finding her i know the foster parent's name and i have my daughters original social security number . i have 6 years to plan what i need to do to try to find her please help i dont even know how to go about it they may have changed her name , gave her a new social , new birth certificate what do i do i dont want to disrupt her life i just want to know she is ok , and to own up to my mistake and to let her know i have changed and through it all i have never stopped loving her