A book on The Intelligence of Dogs published a list of dogs in order of intelligence. Beagles were ranked very low on his list. The intelligence was measured by ability to understand new commands and obey the first command.
Here are the top 10 Brightest Dogs:
1. Border Collie
3. German Shepherd
4. Golden Retriever
5. Doberman Pinscher
6. Shetland Sheepdog
7. Labrador Retriever
10. Australian Cattle Dog
Welsh Corgi (Pembroke)
Beagles aren't mentioned until #72.
Thankfully, they go on to explain that
"Intelligence is a complex subject. A breed of dog that does not learn very quickly may have other talents. It is important to remember that intelligence should not be judged only by the willingness to follow obedience commands. The willingness or ability to be obedience trained may reflect a desire to please or a dependence upon humans, as well as intelligence...
Hounds may also suffer from this type of ranking. These dogs are bred to have more of a "pack" mentality with other dogs and less reliance on a master's direct commands. While they truly may not have the same kind of intelligence as a Border Collie, they were not bred to learn and obey commands quickly, but to think for themselves while trailing game."
So Maggie has a mind of her own. There is nothing wrong with that!