She is 79 years old and is DEFINITELY showing signs of Dementia/Early Alzheimer's. She often forgets conversations, places she has gone, bank transactions she has made, etc. We are trying to step in to help, as she was never married nor had any children. We are her next of kin. We legally have no right to her medical records, yet we do have a POA and a HCP. However, she refuses for us to take her to the doctor, because we are hoping to get a mental status check on her.
She was afraid to go. I think deep inside she was afraid of what they might find. So, your aunt could really be scared deep inside. Try to help calm her fears and don't act like something is terribly wrong with her.
Can you convince her to go with you TOGETHER so you both can get your flu shots? You can write a note to the doctor listing all that you have seen in advance, so he knows what's going on. Then when you meet with him for the flu shot, he can chat with her, ask questions and figure out what her problem is. They might need to check for UTI too. Sometimes, that can cause dementia symptoms.
And when she says there's nothing wrong with her, well good! Then the doctor will confirm it, and she can enjoy telling you she told you so.
(Or not, of course, but you don't have to remind her about that bit.)
I am the legally appointed proxy for an old friend (now 85) who 10 years ago was living alone and hiding the fact that she had already been diagnosed with early onset Alzheimer's. Crooks and thieves were causing her to empty her bank account and savings. I tried to stop it at the bank but was told that the only way was to get a legal proxy signature. Luckily my friend agreed to write the letter to the local judge to ask for help, when she learned that this would get rid of the crooks.