Vet questions

I got my dog when I was 11 for my birthday and she’s always been my dog and responsibility. My parents think vets are waste of money and aren’t willing to take her unless it’s life or death. I’m always worried about her health. She’s 6 now and I would love to get her checked out and get her teeth cleaned (she has horrible, horrible breath). I was curious if I am able to take my dog by myself since im still a minor and how much a check up and teeth cleaning usually costs (willing to pay any just curious). Also she absolutely hates strangers, barks her head off won’t calm down until they’re gone and won’t let people touch her. (Doesn’t bite but snarles and barks, she’s 8 pounds so it’s not a fear of her hurting them, but hurting herself or not being able to do the checkup). I know it’s horrible, I wish we socialized her more. Are they be prepared for dogs like this, how would the appointment work when she acts the way she does?