To work with other people for a higher goal, instead of hiding away all by herself. And that’s just the most superficial lesson and I haven’t seen the movie since it was in theaters. There is probably even more if you actually looked for it.
If that were the case, why does she effectively betray the rebellion? It would make more sense if the rebels were the ones who were going to sacrifice themselves regardless and it’s Jyn, not Ackbar ripoff, who comes last second and turns the tide.