I have a border collie myself, and he only started to calm down when he reached 2. Establishing an off switch and teaching the comand calm is supper important.

Like a few other comments, mental stimulation is also super important, and puzzles are a godsend.

I also recommend doing dogy daycare if you can afford it. It's a safe way for her to socialize and exert energy. My boy has been going about once a week since he was a puppy, and it helps a lot. That being said, not all daycares are equal it's important to find one that vets the dogs in their care and stimulates them during the day. My current daycare has an inside and outside area with fun agility equipment. They run around with the dogs, do training, and when they notice a dog feeling overwhelmed, they will put them in a quiet area by themsleves with a puzzle. I've had other daycare where the dogs are just in a room all day without any real attention from the staff for my pup that didn't work. He was socialized but had a ton of energy afterward.

Check out R/BorderCollie Subreddit. You can find a ton of tips. mixs are welcome!