Table.RemoveColumns based on the date - excel

Question

I am looking to insert a remove column step which removes any column where the header (which is a date) is before a certain date (older than X years prior to the current date). I receive a large data dump which is just a list of client names and fees they pay each month from 2012 to today, headed by the month they pay each fee, but as time goes on I don't need the oldest of the data.
So far I have tried producing a list from the headers (based on a previous response from another board member - thankyou #horseyride!) and then removing the columns which dont meet the criteria FROM that list. However it keeps breaking.
This is the latest line in the advanced Editor
#"Pivoted Column" = Table.Pivot(Table.TransformColumnTypes(#"Removed Columns", {{"Calendar Period", type text}}, "en-GB"), List.Distinct(Table.TransformColumnTypes(#"Removed Columns", {{"Calendar Period", type text}}, "en-GB")[#"Calendar Period"]), "Calendar Period", "Approved Invoice Amount", List.Sum)
This are the lines i am attempting to create:
"ColumnList" = List.Select(Table.ColumnNames(#"Pivoted Column"), each Text.Contains(_, " ")),,
"Delete Columns"= Table.Transform(#"Pivoted Column", Table.RemoveColumns(#"ColumnList", each {})as table)
in
#"Delete Columns"
the Second bit of code I cant seem to get right - that is what I believe it should look like for now. But essentially i want the table to remove any columns where their header (a date) is prior to X amount of years older than todays date.
EDIT - Screenshot of before and after IF the desired cut off was Dec 2012:
Example Data
Thank you in advance

Answer 1

Just use following code. For static date:
let
Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
final = Table.SelectColumns(Source, List.Select(Table.ColumnNames(Source),
each try Date.From(_) >= #date(2012,12,1) otherwise true))
in
final
For dynamic date (older than 3 years prior to the current date):
let
Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
final = Table.SelectColumns(Source, List.Select(Table.ColumnNames(Source),
each try Date.From(_) >= Date.AddYears(Date.From(DateTime.FixedLocalNow()),-3)
otherwise true))
in
final