Some people don’t want you to succeed. They don’t want you to grow and will do all manner of things to sabotage you. Why? Because it makes them feel safe. Prove them wrong.
If someone tells you that you can’t do something, you simply need to make a mental note of it, figure out how you can prove them wrong, and go and do it.
There is right way and wrong way of doing this. Let your actions speak for you.
Don’t make a big deal about it.
You don’t have to show off.