Adding information to notes section to users through CSV

Hi All,

I'm trying to write a script where I have a CSV with First_Name,Last_Name,DOB. What I would like is for my script to search through a defined OU and add the information from the DOB column to the user. After the script looks at the right OU I want it to look through each user and find the ones that have a First_Name entry to match with someones $user.GivenName and Last_Name match $user.SurName. Once it does that it will add the information next to their name in the DOB (Birthdays) in that user's Notes section in their AD profile. I thought I had it right but I think I am off but here's the current script:

#==============================================================================

# File:    notesCSV.ps1

# Author:  Jason Singh

# Date:    07/01/2016

#==============================================================================

#This is needed to supress errors, in this case to supress null path errors.

#$ErrorActionPreference = "SilentlyContinue"

#Imports AD module...

Import-Module ActiveDirectory

Import-CSV c:\Test.csv

 foreach ($user in $users) {

  Get-ADUser -Filter "First_Name -eq '$($user.GivenName)' And Last_Name -eq '$($user.SurName)'" -Properties * -SearchBase "OU=Students,OU=xxxx,DC=xxxxx,DC=xxxxxx" |            

  Set-ADUser -Replace @{info="$($_.info) DOB"} 

}

And an example CSV would be:

First_Name,Last_Name,DOB

John,Smith,01/18/2016

Jane,Doe,08/04/1998

Any help is appreciated, thanks!