Question about size

Hi, my name is Joanne and I have a 15 week old Goldendoodle named Armani. She is a delight! I am going to be training her as a therapy dog. She has the perfect temperament for it. My question is about her size. She is about 15 pounds. She was 7 lbs. when we got her at 11 weeks. The breeder assures me she is a standard size, but the vet and the trainer (she is in puppy kindergarten) say she is very small and must be a mini. I will love her no matter the size but was looking forward to a big dog. Any one out there that can give me a comparison or size of your dogs at 15 weeks.
Thanks!