Determine Folder Size, then delete oldest file...

I need some help from an expert.
1 - I need to determine the size of a folder
2 - If folder size is larger than X MB goto to 3
3 - delete oldest file in the folder until folder is no longer larger than X MB
Is this possible?
Thanks in advance
1 - I need to determine the size of a folder
2 - If folder size is larger than X MB goto to 3
3 - delete oldest file in the folder until folder is no longer larger than X MB
Is this possible?
Thanks in advance