Sounds good!
Some of the common mistakes are made by native speakers too! Stuff like Dialogue Punctuation is a common problem even for good writers.
I imagine it is just generally not covered well in school, so you either pick up on it by reading (but who pays attention to punctuation?) or learn it elsewhere. But if you don't have an editor, where else will you learn? Strangers on the internet will tell you, of course! Or, you know, you'll learn professionally.
Anyway, your writing looks solid from what I can see here, but seeking feedback for a smaller section is a good way to avoid having to change a lot in case you are making a certain mistake consistently (such as dialogue punctuation).
Longer sections are good for pointing out any issues with the broader strokes tho (like overall pacing, or an inconsistency that only happens after multiple pages).
Most other mistakes can generally be caught with proofreading, and perhaps speaking (or mouthing) the words.
I guess stuff like there/their, where/were, quiet/quite, etc, might not be, but as long as you pay attention for if someone does point such a mistake out, you can learn to avoid such mistakes in the future.
Oh, when proofreading, do be careful to read what is there, and not what you think is there.
I guess also google any words you're not 100% on, since I know certain things didn't actually mean what I thought they did (and sometimes I'd just like the sound of a word, lol).
Anyway, remember to write!