I'm a first time B owner as well, so can only go on my own experiences with Loki and other dogs I've owned or dogsat for, but I also wanted to bump this post up so other members could see and respond.
She is definitely not too old to train. Dogs of any age can still learn, however it can take more effort and diligence, For example, my aunt has a rescue Bloodhound whom she brought home when he was about 4 yrs old. This dog had never been in a house and had been abused by the man who owned him. At 12+ yrs now, he just retired from doing K-9 Search and Rescue and he is just a huge teddy bear despite his 4 yrs of neglect and abuse. He does not live in the house as he was terrified every time they took him in and never could adjust, but he's a good example of what dogs of all ages can overcome and learn.
Loki will be 1 on the 29th. He still chews and I don't expect him to stop anytime soon. Our solution is to have a lot of chew toys! There are times we have Nylabones and antlers in just about every room of the house. In fact, I just remembered I need to order more bully sticks I used to sleep with a Nylabone under my pillow because if he woke up early in the morning he would lay there and chew on the sheets, so I kept one close to stick in his mouth whenever that started. We also try to keep him tired out which involves daily walks, weekly dog park trips, and quite a few play sessions during the day. If he is bored, he will literally look for trouble. He also likes to dig when bored and our solution to that is simply no unsupervised outside time. Now that he's older we've begun letting him out without us being in the yard with him, but if he digs, in he goes and it's back to being supervised. We also indulge his destructive desires by keeping the boxes from any packages we get, tossing treats in them, and letting him get them out. He even gets some newspaper and empty envelopes sometimes. As a result, he assumes all boxes that come in are his to destroy, but I'd much rather have that than him ripping clothes or eating shoes.
How much exercise and crate time is she getting? What does she have that she is allowed to chew on? And what are you doing to distract her when she starts to chew? Hopefully some of the other more experienced B owners will see this thread and pitch in now. Sorry for the very long reply, but I figured I'd give you examples of my own experiences and what works for us.