Profanity is allowed to some degree. Also, first sexual experience is allowed but do not go into very much detail. I recently retired from a middle school and books were selected for the students to read and discuss, to write reports on and to interpret. The school district would buy these books by the hundreds. The books that are selected will have no profanity at all. Students are still offered selections to buy from the Scholastic Book Club, again no profanity. I don’t know about other school districts and their guidelines for books
Young Adult will probably include more high school students than middle school students. You will have a little more freedom of expression with the older students. If you only have two words, sh** and bast***, I don’t think you’ll have much of a problem. But at the same time, I’m sure that there are some places that would turn it down because of the profanity.
If you think that the level of profanity is appropriate for the story, then go for it. If someone turns it down because of the profanity, then you can always take those words out.