It's the old adage, "you need to learn to lose before you can learn to win." That being said, you don't want a new kid to be last for long. That can suck the fun out of it in a hurry. You need to see progress form year to year.
I'm a bit confused! First you ask if this heifer is worth putting in the work? Now you say she should have won the whole show. So you are obviously already an expert and don't need our advice.
They asked if she was good enough or worth the work to compete in a big class at their state fair, which sounded like they were on the line about taking her cause they weren't sure how she was going to stand in the quality of those harder classes. They didn't mention or ask if she was good enough to compete in their county show. I think they knew she was good enough to well locally. There are many people who know that their animal is good enough to compete at the county level and can think they should have had purple banner there yet still not know if the heifer is good enough to haul to their state fair.