Accept criticism and embrace them. Let me rewrite that, embrace thoughtful and honest criticism and incorporate it into your writing.
Not all criticism is good and not all good criticism is useful. If you’re writing in a genre that your mom doesn’t enjoy and she read your work, 9 times out of 10 she won’t give you a good critique other than umm the writing is good but the story not so much. It was not bad criticism but not good either it’s more like impartial criticism; and that’s the kind of criticism you don’t want.
You want a reader in your genre to read your book and give feedback you can utilize to incorporate in your writing. Beta readers are great the trick is to find a reliable, trustworthy, and dedicated beta reader. But once you have them treasure them because they’re awesome.
Criticism is like your high school English teacher’s red ink everywhere on your perfect essay. Psst there’s no such thing as perfect writing so don’t fret about writing to perfection because there’s always room for criticism and improvement. Trust your work. Sometimes someone reading/criticizing your work doesn’t see your vision and that’s okay simply listen to what they say and use it if it’s good or use it for another project or don’t use it.
If the ‘opinion’ was downright rude then make a mental note not to use that person in the future. Bottom line accept criticism that works for you.