Mom seems to have memory issues, should I be worried?

My Mom, within the past five months, has gone to three medical appointments that did not exist on those dates at those places. For one, she drove to an optometrist, which was closed, when she actually had an appointment at the hospital for a CT scan. For the second, she drove to her local provider’s office where she was not scheduled when her appointment was actually for the rescheduled CT scan at the hospital in another town. The third time was a week ago when she again drove to her local provider but was not scheduled for an appointment there at all.
I also noticed yesterday that she has not reordered checks for her checking account. I had shown her the reorder page in her checkbook two months ago but she is still out of checks and seems to be either unable to order them or unwilling to.
On Saturday she purchased four bouquets of flowers for gifts and left them laying in a dish rack without any water, I found them on Sunday and cut the stems back and put them in a vase to try to save them. She has no idea why she didn’t put them in water on Saturday.
Last Friday, we went for a drive, and at the restaurant drive through, she watched a man in a van order and then said, “The man in the big thing just gave his recipe.” Then she said “gave his menu”. I suggested that the word might be “order” and she said yes, that’s it. On the same trip we went to a nursery to pick out plants. She walked over to the creeping phlox and said, “Look how beautiful these are, I have these growing between the stones in my walkway.” They were beautiful but the problem is that she has Johnny jump ups growing between the stones and has had them for decades. She doesn’t have any creeping phlox at all and they are not even similar except for being used as ground cover.
My Dad bought her a cell phone for Christmas and I helped get it set up and put in all of her contact numbers so that she could choose by name who she wanted to call plus showed her how to make a call and how to access the internet. She tried it maybe twice and put it back in the box and just won’t use it. Again, I don’t know whether she had trouble using it or just refuses to use it. She won’t say. It was purchased so that when out she would have a way to contact people, especially in an emergency.
Am I worrying for no reason? She has not been diagnosed with any memory care issues but when at the appointment to have a check up for just that, she told the doctor that she only got confused about one appointment but in reality it was three. The doctor said that mixing up one appointment is not an issue. So the doctor doesn’t even know about the rest of it. My Dad is mad at me for being concerned. He just says that she’s forgetful. I just don’t know.