As you've seen from the linked question, we do not object to people asking questions on Shabbat. If you are Jewish then you might want to discuss use of computers on Shabbat with your rabbi, but that's a personal matter for you. If you aren't Jewish, you've done nothing problematic by posting on Shabbat and have no reason to be concerned.
That said, I'll make two arguments for just leaving it alone instead of trying to remove it if you did post and you worry it's a problem:
If your concern is that you've violated halacha by posting on Shabbat, then you should also be concerned with doing more on the site to try to undo it. Better to just walk away than to compound the Shabbat violation by doing more. (This happened to me once on this site, by the way.)
If your concern is that people will see that you posted on Shabbat, deleting it won't completely hide that fact anyway. If you were to delete the post on Shabbat and undelete it after, the posting date would still show. And if you leave it deleted it's still visible to higher-rep users. A question that you asked and deleted might never be noticed, but an answer probably would be.
So, bottom line: if you're not a Shabbat-observant Jew and are only worried about appearances, then don't be worried. If you're a Shabbat-observant Jew and goofed, presumably you're more aware and will be more careful in the future but there's nothing to do in the moment. And if you're a Jew but not Shabbat-observant, but you're experiencing some "I shouldn't have done that" feelings, there's still nothing to do in the moment but maybe this is something you want to reflect on further and/or discuss with your rabbi for future consideration.