Changing Nipple Flow?

Vicky • 28 yrs old - Dog lover - Eats everything
My 5.5 month old hasn't been sitting still during her bottle feedings. She's currently on Dr Brown's level one nipple (slowest flow) and I'm wondering if she could be frustrated with the slow flow of her bottle. Should I try level 2? Or is her fidgety tendency is nothing to worry about?