I was trying to create a Fairy Mage, I was rolling stats over and over, when this happened.

I was lucky if I got 17, but this... I didn't even know it could surpass 18 O_o

Edit: Though she got only 2 Karma. I know that's really bad for creating a character, but regardless, I am not wasting this opportunity.

You were very lucky. It's possible to get a roll of 21-26 but it's very unlikely, I never got more than 18.

The Manual said that it's basically a luck stat, and determines my overall success.

Most of my characters had low karma. Don't worry. It's even less useful than the almost useless personality.

I remember spending at least 2 hours to reroll all stats above 17 in Wizardry games, and the highest stat I have ever got from rerolling hundreds of times is 24 in strength.

Personally, I don't bother with heavy re-rolling, because you gain stats by leveling and lose them when you class change anyway, and the game mechanics heavily favor class changing over staying in one class. (Wizardry 4 and 8 excluded, of course.)

maybe that is why I struggle in wizardry 6 or 7, I just don't like to class change in many games, as u stated loosing stats, which I don't like to do.

Without class changes W6 and W7 are definitely quite tough, or at least they require lots of grinding, like trainging skills early on without leveling up (in order to not lose skill points automatically spent on primary skills).

If you worry about losing stats then I don't think it's a big deal because you level-up again superfast anyway.

Personally I do like the whole planning process involved with level-ups. At the time I had some very elaborate plans to level up my characters in 4-6 steps to their final class, collecting all there is to gain along the way.
However, I don't like the idea of the concept of losing all your attributes. Why on earth would someone lose most of his intelligence by changing his profession? It doesn't make sense.