I would be getting worried. Is she still teething? I have a pup in a similar situation although one ear is up now at almost 20 weeks. Some have them go up as late as 9 months but that is far from the norm.
Have her ears ever stood properly, even for a day? If so, they’ll likely go up again. I would give it another month, but I’m also not one to mess with ears. If you’re really worried and need her to have erect ears, you could tape them, but you’ll have to learn how to do it properly or you could risk damaging them.
If they went up before, they'll come up again. Are her ears particularly large for her head? Do they sit lower on her skull? Have her puppy teeth started to come out?
Kodi is the same way at the moment. He has very large ears that sit wide on his blocky head. He's 4.5 months old, just losing his teeth, but now that they're finally coming out his giant ears are starting to stand for a few minutes at a time each day (longer and more frequently as each day passes).
Jack's ears were standing at 4 months, but he lost his puppy teeth much sooner and his ears, though large, sit higher on his head.
My 16 week old Reagan(Rea) is from East German bloodline. Big head, ears, and legs. Her left ear is up all the time and her right ear maybe half the time. She's about 40 lbs and my breeder said not to be surprised if her ears aren't up permanently until 6-8 months.