I'm confused. You said she measured the crank and said the bike is too short. Is the frame too short or are the cranks too short?
The crank is only 1 thing a fitter will look at and it can be changed to a longer one, but what about the size of the frame? How does it fit? If there are major fit issues then definitely you'll want to see a good fitter and get a new bike. If the frame fits with minor adjustments then switching the crank is not a big deal.
How much will it cost to fit the bike vs buying a new one?