Honestly, this is probably a good thing. I have read a book recently concerning puppy "manners" and how the puppy in questions had to ask "please" by sitting for anything they'd like. It seems like she's ahead of the game and knows what she needs to do to please you, ie get treats. What I would do is change up the order of your requests (ie, sit, down, stand, sit, stand, down) by varying them more she will have to be more mentally engaged and will wait for your command. Also if she is solid in both commands add more simple ones, or vary the complexity. for example, if you're teaching her to wait and then release on command vary the time lapsed, the distractions, and the motivations. With my puppy, I taught him to sit and wait when i throw a toy or treat and when i say Free he can go (it's never a very long wait, but he will wait as long as i want). In order to change up the difficulty level of this exercise I used different toys and treats, worked with him outside with other distractions like neighborhood dogs, cars, etc. Make sure if you're outside though you are safe in either an enclosed yard or on leash
It's a good thing if she needs more mental stimulation! That means she's getting it and can handle more!
good luck!