You are, obviously, more than welcome to post on the forums, just be aware that the responses you get will be from peers rather than instructors at least for the most part. They do drop in on occasions, but on each visit there would be so many posts that trying to keep on with them all would be impossible. The Q&A provides a mechanism where, as a student, you can be assured of a response.
Regarding the ignoring, it would be better to ignore them, you’ll find that Unity creates a copy of the project and pops it into the /library/ directory, so your working directory size can get fairly large - if you commit it all to source control, whoever else grabs a copy has to get far more than they need. And yes, the .gitignore file is acted upon when the repository is opened, so these files wouldn’t be listed under a non-staged view for example, so thus, less to stage, less to commit.
One of my own experiences with a team of developers who didn’t set their .gitignore files correctly created a scenario where there were different user preferences being committed by different team members. This made for a fairly miserable time, as little things like the number of spaces for tabbing and line ending encoding etc was being constantly changed, which impacted upon the next developers environment… Not fun… many arguments…