Pulling "MIN" Data From Another Sheet (Error Detection)

This community is always so helpful, hoping you can pull another one off for me

I have attached the workbook with the goal of pulling information from the sheet "CallTek" into the "Daily Tickets Report" sheet cell D6. Currently I am using the following function: =(CallTek!P2)

This works only if I presort the data on the sheet "CallTek" so that the oldest ticket date is first in cell. The problem is if the reference cell is null than it displays "0" when I want it to display "N/A"

Someone on this site provided a function that works in the other rows in column D - only if they are in a date form like #/#/## however if the reference cell says "# days ago" it breaks the function. This function provided was: =IF(COUNT(SheetName!M:M)=0,"N/A",MIN(SheetName!M:M))

Goal: Display "# of days ago" or "N/A" if reference cell is null -AND- if possible pull the oldest value such as "2-months ago" over "2-days ago"