effect of data sources in dimensional modeling

Hello
Is it possible to remove something from dimensional model because there is not anything about it in data sources?
for example :best dimensional model is based on REAL data that determine with business process
now if I want to fill a dimension table  that not have anything in data sources for it ,how can I fill it in ETL process?

Make it up?

I don't follow. Are you talking about a packaged 'standard' data model?

If you don't have data suitable for the model, change the model.

for example I want to store customer age in customer dimension table,
but in all data sources that I can use there is not anything about customer age.
what can I do?

Sometimes dimension attributes such as customer age can be calculated in the ETL process. In case it's not possible and they cannot be sourced from any source, they can be manually edited by business users - for instance with special web application dedicated for that purpose

ok, thanks.
therefore, not only data warehouse tables data fill with data sources in ETL process,but also business users can change data warehouse tables data with some applications, for example web applications.
is it true?

True.
In the global data warehouses of my clients it's normal practice.

thanks so mush.
I found my answer...