Is AGE a big factor of interest when hiring people with skills ,or professionals?

Accordingly to me Skills should be more important.

professionals and experiance 

Depends. The post yo are hiring for. It can be big factor while hiring a Manager if he is already 59 then what he can lead to when he will be 60 next year? similarly hiring young people will bring more adaptability culture to new technology usage and you can make them assets as they will stay long provided your company takes care of their employees.

No. Clearly an act of immaturity. 

Only if you are a prejudiced person.

Discrimination based on age is illegal in many countries, and is invariably harmful to the business.