Before you decide to start training consult your doctor. Get evaluated to find out if you are fit to do the hard training needed for this program. Set some achievable targets. It is tough to start with and it will be tougher to stick to this program. But, make a promise that you will stick to it for at least 3 months and not give up unless, it is for health reasons. Also, start slow. Don't overdo in the first few weeks and end up injuring yourself.