HemisphereDancer,
As a father, if my son decided he wanted to become a pilot, I would support him fully...it is an amazing job with a huge choice of career opportunities, especially if you are prepared to leave your domicile. I would also STRONGLY recommend he learn how to fly OUTSIDE of the airline ab-initio training systems, and spend the first 10 years of his piloting career gaining some experience. This would benefit both him, and the industry. Yesterday I was asked by a new joiner if I have ever heard a Mayday declared in my 11 years at Cathay...my answer was "...actually no, but I have declared 2 or 3 myself before coming to Cathay". This was met with surprise...and is indicative of the very safe nature of airline flying compared to what is available in the aviation profession.
If I was an airline recruiter, I would also prefer to hire pilots who have prior experience. Certainly for me personally, the highlights of my flying career were prior to joining the airlines. As a 20 something year old, you have at least until age 65 to fly...spend the first 10 or so years gaining some great experience somewhere (GA, military, Africa, PNG etc) before strapping yourself into the very safe and benign airline environment.
Unfortunately, much of what is stated in previous posts is correct...prior experience is not particularly highly valued by airline management. They are concerned with bums in jets, so as long as you have the minimum requirements, you simply have to win the recruiting process battle to get a seat.
Do yourself a favour...go and have 10 years of amazing adventure before settling into the easy retirement job!
Jason