Is age or age difference a problem in leading a team of co-workers with some of them older and more experienced?

I have a personnal experience with above mentioned issues, I can say in a professional way that you may have some challenges & you can use replacement to enhance harmony in your team with time & day to day practices.

i faced that in the past it is not easy but you have to set roles from begging and revisit the role from time to time be straightforward and friendly with clearly setting borders

Great Question ! Managers are increasingly grappling with generational differences in their work forces.
Problems can arise from differing mindsets and communication styles of workers born in different eras.
The frictions may be aggravated by new technology and work patterns that mix workers of different ages in ever-changing teams.
Baby Boomers, born between1946 and1964, are competitive and think workers should pay their dues, workplace consultants say.
Gen Xers, born between1965 and1977, are more likely to be skeptical and independent-minded.
Gen Ys—also known as Millennials—were born in1978 or later and like teamwork, feedback and technology.
The key is to be able to effectively address and take advantage of the differences in values and expectations of each generation.
But experts say managers must be careful not to follow blanket stereotypes.
Managers must also take care not to disadvantage older workers, even inadvertently, or risk retention problems and legal headaches.

Age is not a problem if the person has the qualifications and experience of good

From a people dynamics perspective - yes.
Some of the older and/or more experienced colleagues will definitely not embrace the younger person unless they have worked with them before or know their reputation.
I faced this when working on a project.
It was a matter of those knowing my work and through consistent behaviour proved to those not in favour of my position that I was capable of doing the job.
I did this through engaging them and also showing respect for their position and being teachable.
Always be100% certain of the facts.
From a job perspective - it should not pose a problem.
An individual is appointed to a positon based on their competence and also that executive management has confidence in their ability.

This is a good question, and people usually face this. I have personal experience dealing with such situation. In the beginning I used to hesitate ask senior people of solving urgent problems, stay late to resolve an issue which I realized is not correct. Slowly I built up trust with them by communicating their roles and expectations from them within the team and company's business objective; and set role for individuals within the project team. I communicate objectives, goals straight-forward and set roles for individuals clearly during project kick-off meetings. Now also I have people above my age as my direct reports and they do not have problems reporting to me. It's important to make them feel that they are important part of the team, and you have high expectations from them being seniors...

i do not think so---age is not an important factor

in the context of professionalism, this (generation or age gap)  will not be a problem anymore - when a younger Project Manager manages the projects with some of the older Project Managers, supervisors etc. It all boils in the qualification and epxerience of the younger person leading the Team towards the business objectives of the company or organization. 

I believe age is a factor that need to be considered, especially in Arab culture, by showing respect to experience and knowledge, however, it needs to be limited to a certain extent, after all, the leader is the driver for the department/project, and a good leader will motivate others to follow, no matter their age or experience is.

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