。
My mother is the one who made me who I am today.
Literal
Mother [subject-が] me [obj-を] present [gen-の] me [into-に] made-for-me.
The AをBにする ('make A into B') causative-change pattern, where A is 私 and B is 現在の私 ('the present me'). ~てくれた frames the transformation as a favor. Repetition of 私 ('me' as object and 'me' as target state) is unusual but deliberate — the point is the identity between the person transformed and the person she became.