Looking at the raws on Rawkuma, it seems you've translated chapter 17.3 instead of 17.2.
You can find all raws up until 18.3 here: https://rawkuma.com/manga/suterare-seijo-no-isekai-gohantabi-kakure-sukiru-de-camping-car-wo-shoukan-shimashita/
No worries. You're human and not a professional so errors may arise. Some would say "are bound to". All in all, you're the one providing the efforts here so you have the last word in the translation and since it wasn't preventing our understanding of the story (just some hiccups, but far, far...
A "fight lesson" would refer to learning a specific fight, like how to beat a boss in a video game. A "fighting lesson" refers to learning how to fight in a general sense, which is the meaning here. Still missing the 's' to "lessons", anyway, since she's not teaching him only once ;)
Yeah, 2...
Thanks for continuing the translation. A few errors though (nothing that prevents understanding):
page 2
hang out -> hangout
page 5
Tsukike -> Tsukiike
page 8
Do you best! -> Do your best!
page 11
fight lesson -> fighting lessons
page 14
toavoid -> to avoid
a failing grade too the year too...
Mediocre translation? Why not. Not like it's a professional translation website.
The obnoxious watermarks over the drawing like you own the author's work? That's a big no-no.
A café where customers don't come to drink coffee... WTF? It's in the name. X)
...
Just checked the raws: it's "kissaten" (TEA house or more litterally, tea-drinking shop). So that's just an translation error.
Page 6 is a mess
"you complement" -> "you compliment"
"It is because my inability to quell the frenzy has led to days of unbearable suffering." -> The syntax makes no sense. "because" is missing a "that" later in the sentence or an "of" just after.
"why do I not harbour resentement" -> it...
She implied that months count on the 29th of February when she said "I'm counting on you for March", March being the 3rd month. (link to the page in question)
March is even written in big in the raws with an arabic 3 instead of the kanji to point it out, so (3月 instead of 三月): link to the pixiv...