I was 6 or 7 years old the first time I played a full 18 holes with my dad, not sure if we played by the proper rules but I remember that I shot 121 (Probably with a few mulligans). I think I still have that 20+ year old scorecard somewhere in my parents basement, I was pretty proud of myself from what I can remember.
I like to think I leave the course better than I found it. This includes ball marks, divots and trap raking (not that I am ever in traps). I fix lots of ball marks on almost every hole. I play mostly private and they are not a lot better than the public courses I play on.
I use a single tine tool or a tee. FWIW at a country club that I play regularly they give out the single tine tool and their "how to" specifically says do not twist a forked tool it breaks the roots.