Nothing is unrealistic
I have noticed people having many limiting beliefs, especially after the start of the placement season in my college. They think it's over for them because they can't clear the coding rounds, while in reality, they just need to put in some more hours.
But I understand where they are coming from. The dread of past failures is holding them back, and they are so caught up in their own heads that they don't take the next step—in this case, practicing more problems and giving their best.
If you had told me a few years back that I would give a speech or lecture of my own volition in a seminar hall full of 300 people for 2 hours, I would have laughed in your face.
If you had told me that I would be running nonstop and enjoying running, looking forward to marathons, I would have laughed again.
If you had told me that I would be reading books and spending my monthly allowance on buying books instead of going out to eat, I would have thought you were crazy.
But all of this happened, and I am really grateful for these experiences. What I am trying to say is that your past may be the cause of your current situation, but it doesn't have to define your future.
Ask yourself this question: What are the things that I can't do? Then examine the answer—whether it's physically impossible or just your limiting beliefs in action.
Nothing is unrealistic; you just have to be a little more open-minded.