She's probably still getting used to her surroundings. Some dogs get used to it with a snap of a finger, but it takes time for some dogs. I'm guessing she thinks she's the dominant dog now? How is your other Beagle acting? Try to do everything with your other Beagle first and then with her second so she'll realize that he's the dominant one. For example, if you're giving them treats, give your other Beagle a treat first and then give her one.

I could be wrong, but I'd just give it a little bit more time. Congrats on your new addition! I love Beagles too!