Hi, I'm new and I downloaded this font file casually without really thinking because I was just scrolling by and then I noticed that the author requires a donation for personal use so I deleted the file and haven't used it for anything before deleting it except opening it up to see how it types, should I still contact the author and tell him? or is this not as a big deal as I think it is??

You can try the font without have to do a donation.
You have (just as ethic duty) to do a donation only if you want to realy use it.