>>74544818She could beat the main story today depending on how well she does. Buu saga is around 4-6 hours for the average player and her average stream time has been between 4 to 4 and a half hours, but since Peko has a tendency to get hit by literally everything (even though there's an easy way to negate damage from any move) she might get stuck on some fights for a while.
If she does all the DLCs, which I think she might, we're looking at quite a few more streams.