I’ve not done one that old but see no issue with it mine was about 18 months so he had a full grown tail and it couldn’t be any easier.
It wasn’t my idea but someone posted instructions that I followed . I clipped hair where I wanted it , took a piece of 1in pvc cut an angle on 1 end to roll band up on it , slid over tail and rolled band off the other end between joints. She’ll probably chew at it for a few minutes then won’t even notice it.
And like Marshall said brand new dog after that . All of mine have bloody tails but don’t seem as bad as his was , when he got to point he had to stop and chew on it ever so often it had to go