copying files from daily folders using Powershell

I am looking to move daily created files each day to another folder. These files are saved to the relevant YYYY\MM\folder each day. Now I have created a way to move these files over using the year/month date function, however because there a number attached to the month, i.e. December looks like "12. December" it becomes a little tricky.

I tried to amend this with an If statement which would assign "a" to the relevant number corresponding with the month however it doesnt work.

$year = (Get-Date).Year
$month = Get-Date -Format "MMMMMMMM"
$day = (Get-Date).Day

$a = ""



If ($month = "January") { $a = "1."}
Elseif ($month = "February") { $a = "2."}
Elseif ($month = "March") { $a = "3."}
Elseif ($month = "April") { $a = "4."}
Elseif ($month = "May") { $a = "5."}
Elseif ($month = "June") { $a = "6."}
Elseif ($month = "July") { $a = "7."}
Elseif ($month = "August") { $a = "8."}
Elseif ($month = "September") { $a = "9."}
Elseif ($month = "October") { $a = "10."}
Elseif ($month = "November") { $a = "11."}
Elseif ($month = "December") { $a = "12."}



$month = Get-Date -Format $a" MMMMMMMM"


Copy-Item -Path F:\BB\$year\$month\Scan.pdf  -Destination F:\BB

Any idea how to fix this/where am i going wrong. This is my first time writing in Powershell.