My puppy has began resource guarding. How do I stop this?

Now that you know a bone is high value and she will want to guard it, you will need to be aware of putting yourself in the same situation again. Resource guarding of high value items is a normal canine behavior but with puppies we have not yet built a training relationship so we can't ask them to drop things and it can turn into a fight that will negatively impact your future interactions with your puppy.

I would highly recommend Raising a Puppy with Michael Ellis if you haven't watched it. It's about how to set up your puppy for future training and how to manage them so you aren't accidentally creating habits that can be troublesome later.

I only give puppies bones when they are in an expen or crate and then I will call them out to me and trade them for a REALLY high-value food reward, pieces of steak or cheese or whatever she absolutely loves. I don't reach in for a bone unless the puppy is no longer in the area. I avoid conflict with puppies at first because I have no way to communicate with them like I will later once I've established a training relationship. Puppy raising at first is all about management.

You are most welcome, enjoy your puppy! My parents raised Rottweilers many years ago and they are awesome (but very strong-willed) dogs.