i am not a radiologist or surgeon but physio. it looks to me and consdiering your age that you may have fractured through your growth plate - serious injury. i would tend to err on the side of caution, let it settle in boot and crutches over the 6 weeks and then begin gentle swimming, aquajogging and cycling. i would think you are in a boot so that you can still shower and also do some very gentle movements of your foot and ankle to maintain ROM, circulation and some strength. i would ring and talk over with your surgeon until you are clear what the injury and his preferred pathway is.
like i say potentially serious so do it right. anyone else with better radiological skills comment on my assumption?