Can i fix knock knees without surgery at age 17?

No: You are done growing at that age so no nonsurgical treatments will change your bone and me alignment. The bigger question is are you having problems with it? There is a variation of normal among people in unless you're having problems I would not worry about it. If you are having difficulty you should seek an orthopedic surgeon and a major surgery would be required to realign your legs. This is usually not necessary.