Mohammad, I have to disagree with you. Individuals are individuals. They have varying personalities, experience, and skill levels. Age is of little importance except to someone who is still too young to know any better.

I've been successfully leading commercial software development teams at ISVs for over 40 years and I've worked for and even founded successful software startups. I've mentored developers who are now senior technical managers at major corporations. To do that, I've had to stay at the leading edge of technology and even invent some of it.

You've obviously had some issues working with senior developers which may or may not have been your fault. Not only is your attitude toward age and experience naive and counter productive, but where I work in the United States, it is also illegal. When you grow up, I hope that you will learn that we are all individuals with our own strengths and weaknesses---and that inexperience is not an advantage when building software and running a business, it is a challenge to overcome.