There are many mature pilots whon are looking for their first airline job and are hitting a brick wall with some small- minded companies. They are intent on taking young low houred pilots (nothing personal) who will admit to wanting to climb to the top of the ladder perhaps flying big jets. The problem is that obviously they will not stay at smaller companies for long which incurs high training costs. A more mature pilot would be more likely to stay and progress to captain (and reduce training costs).
The next argument is that older people are harder to train- crap, it is all down to the individual and their enthusiasm. Most mature pilots will also probably have experience and even if this is in light aircraft it is good experience - in command time, dealing with the weather, dealing with people and so on.
The problem is that a lot of these companies follow like sheep and adopt each others policies. There are a few who do not - thank god! Next year legislation comes into force that is supposed to stop this but i am sure they try to find a way around it.
If their are any mature pilots out their who are finding themselves up a creek wiithout a paddle i will interested to hear of their xperiences
I've edited the layout of this post to make it more readable. Please note that you do not need to use the carriage return (enter) key to add a line in the 'add post' area, the software will add new lines where necessary. You'll note that I haven't altered your spelling or grammar! 
Scroggs