In "The Killing Zone" Paul Craig explains that pilots due to inexperience and attitude. Low hour PPLs (like myself) are particularly vulnerable. These are pilots who have between 50 and 300 hours. (Students are amongst the least likely to kill themselves because they follow all the rules). A cavalier or complacent attitude is also a common factor in fatal accidents. Just read the AAIB reports.
Typical scenarios include flying VFR into IFR conditions, not looking out for traffic, poor fuel management and alcohol and drugs. I suggest pilots who think that luck plays a major role attend their local CAA safety evening more than just occasionally.
Getting IMC/IFR training is also a good idea.
Age is not a factor. Experience and being safety concious is what makes pilots survive.