Your puppy is at the right age to be growing its adult coat. In this breed the ‘puppy coat’ is single, with only long and silkier ‘guard’ hairs, while adults have a double coat, with the silkier top hairs and a thick underlayer of shorter, finer, fuzzier fur. This grow-in process leads to incredible tangling! But only for a few months. Additionally your dog might be having a bit of a spring ‘blow’ (major shed). Dogs with this type of coat tend to shed a ton once or twice per year, which leads to incredible matting if you don’t brush all the time, and hardly at all the rest. So long story short, your new dog might not always be so high-maintenance!
Since you are in charge of the grooming right now, my main advice is to brush her constantly (so there are never any severe tangles that will hurt and make her fearful of being brushed), bathe her frequently, and use conditioning agents; both during and after the bath, and while you are brushing her too if she has tangles. A small spray bottle filled with water, with a tablespoon or two of conditioner thoroughly mixed in, can do wonders to detangle and prevent new tangles from forming. There are also detangling sprays you can buy.
Look around for another groomer, if you don’t want to do it yourself. There are many options outside of Petsmart, most doggie salons are smaller and more low-key and might help her be less stressed. You can also usually find someone that will come to your house to do it - that might be easiest for her. But you setting the groundwork for making grooming frequent, low-key, even enjoyable (give her treats and praise) might help her relax next time.
I have a white Tibetan Terrier - this breed has a similar coat to a powder puff Crested. In fact that pic looks a lot like my dog! Is that yours? Very cute.
I would never keep my dog’s hair long. She is a pain in the ass and is constantly finding ways to get filthy, she is pure white so even dust and sidewalk grime shows, and she drinks too much so if the hair on her muzzle is long it’s always wet… bleargh. And yeah, I just plain hate brushing and cleaning long hair. I already bathe her at least weekly just to keep her decent and white instead of gray, and she has hardly any fur most of the year! She’s only been to a groomer a handful of times (she’s 14 years old), I do it all myself: clip her to 1/3" about once every month or two in warm weather (with Andis clippers) and grow it out in the winter when there’s less mud and rotting animals about for her to grind into her fur. It usually gets about Benji-length (similar to the pic your posted, maybe a bit shorter) before the spring. Then I chop off the excess by hand, with scissors, and even it out with the clippers again.
) is mainly white with bits of cream and has brown ears. She is simply adorable.