Ego doesn’t leave easily. If one waits for the ego to be dissolved before one takes up work for the Divine then one may never be able to take it up. Rather by sincerely taking up the work one slowly starts getting rid of the ego.
However at your age (late adolescence) I would suggest that you should right now focus on developing yourself and read Sri Aurobindo and the Mother but without neglecting your main subjects of study. Later once you get a stable foothold on life then you may decide whether to take up this work or any other.
Affectionately,
Alok Da