The most important step you can take to make your dreams have any chance of coming true is to start with a plan. If you have already identified that your basic aerobic conditioning and basic strength are low then these are fairly easy to start working on TOMORROW. Don’t wait.
You won’t need to train 20 hours a week to see big gains. Very few but the fittest professional athletes can manage that kind of time commitment. In the early stages you’ll probably be doing 5-8 hours per week. Our training plans are based off the same principles we laid out in our book. They are designed to gradually build fitness over the long term. There is no short cut and this is a multi year project if you really have big aspirations. Your location in CH is a big plus due to your access to mountains.
There is just no way to predict the outcome for you. I don’t know enough about you to tell you anything other than to TRY. Who knows what may come. I can tell you that embarking on a good training program WILL make your mountain experiences (skiing and climbing) mush more successful and enjoyable.