Should I learn how to do this beginners curveball at 13?

http://www.thecompletepitcher.com/pitching_grips.htm#q6

I don’t know if its the same as normal curves that mess your arm up, so should I learn it or not?

If you’ve not developed a good change-up, then I would continue with that. But, if you decided to work on a breaking pitch, make sure you do two things: (1) do NOT supinate your hand while the arm accelerates forward and (2) limit the number of these pitches that you throw to no more than about 20% of your total pitches.