Yes 1/4" crickets in a big tank might be too small for even a young bearded dragon.
Think of it like this.. Would you rather work twice as hard for a 50 cent payoff or work half as hard to get a $5 payoff? Those tiny little 1/4" crickets are not only harder to see, but probably much faster too! I'd be ordering 1/2" crickets for a baby beardie, and 3/4" and 1" sized as the beardie gets older myself.
Since you have so many of them tho, you might try putting her in a smaller 'feeding' container such as a 5 gallon tank or so just to feed. Make sure nothing else is in there the crickets can hide under either, as this should help her catch them and make it not nearly as much work for your beardie to feed.
Hope that helps!
- Zaxx