I agree with all the other advice--Budgies all have different personalities.
Definitely there's been a lot of "I tamed my budgie in 2 weeks" success stories lately, but don't feel discouraged! My little girl took almost three months to tame completely, as she's always been flighty. Just keep working with her and don't give up--some day the moment of truth will come and she'll reach through the cage bars to preen a strand of your hair or decide to land on you during out of cage time.
You're doing great, keep up the good work!