Saying I have 6years or experience, is it when I started learning it or utilizing it in my projects??🤔

Well when you learn it you usually also apply it or did you just not use it?

Not that it matters anyways, you can literally lie on a CV, as long as you don't do so in person / on a contract.

Also, consider any open source contributions as work experience.

exp grinding is part of the journey and counts towards total hours played

It depends on what you claim you have experience in.

If your first year or so was a little bit here, and a little bit there... maybe don't count it as a year of experience in whole.

At the end of the day, when you started to do this on a near or full time basis, start counting.
Once you break that 5 year mark, no one really cares anymore, once you get past that 15 year mark, your starting to go grey if you haven't already and we call you a boomer.

Depends. real work experience can be quite different from random dead hobby projects and fiddling with things at a superficial level.