Running is harder on the joints, but you're young, you can handle it! I work out for 30-60 minutes per day, 7 days a week. Usually I do a combination of power walking, crosswalking, and/or cardio dance, but every other day I like to try and kick it up a notch and jog instead, but I'm telling you, it's killer on my joints, which is why I don't run on a daily basis! Guess I'm not as young as I used to be!
If it's high impact enough where you can feel it while you're running, I don't recommend it at all. You can tear ligaments pushing yourself too hard. You should ride a bike instead HCM.
I've been kicking around the idea of getting a recumbent bike. I used one in the parents' room while my oldest son was in the hospital last year...I would bring him in the room with me in a wheel chair with a big stack of children's books so he could read while I rode the bike. I liked the recumbent bike better than the usual upright stationaries, felt like my legs were getting even more of a work-out.