a) You are perfectly okay. If Chrome is the browser you like best, make him your default one and get rid of these messages.
b) The many times when you actively open a browser to use the internet, it's not important which one is your default browser. The purport only shows in the situations when another application tries to open the browser. Then it will look into an internal list and choose the default browser.
c) If you decide otherwise in the future: the next time you open the Internet Explorer or Firefox or something else - they all will prompt up a question to be made the default browser. So you lose nothing and you're not bound to Chrome till the end of times.
As HarryT advised you in another thread: try posting in the right subforum.
This is a lounge question.