Date variable for Time Series Modeler

Hi, I have a huge table of DAILY data for 20 years. I have variable of type date, which indicates each day of my data. So i want to use it for Time series forecasting. But it s not recognized as date and I\m forced to define dates. This doesn't help, because thus I cannot use by Date variable, besides, this doesn't provide a way to create dates for all days - I cannot find the right format possibly.

How can I solve my issue?

This is some part of my data:

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