Is My Puppy Old Enough For Training?

My puppy is a 10 week old Cockapoo. The vet says that they recommend waiting 2 more months – until she has completed vaccinations. Petsmart says 10 weeks is fine as long as she is up to date with her shots. She is very aggressive towards both people and dogs, and I really don’t want to wait to get her socialized and properly trained. My mom watches her for me sometimes, and she attacks her dog. Am I putting her in any serious danger by taking her to the class now?