well ask yourself this question ...... do you really love running the same way you love skiing ? or do you just do it cause your good at it ? its sounds stupid but put some thought into it i had to ask myself the same question between hockey and skiing . i definetly didnt have the potential that you had but still i played rep hockey .. i choose skiing and never looked back or regretted
Focus on running, train hard. You can always ski well into your 60s even if it not extreme, your still skiing. But wiht runnging you cant, take running.