Edit: This question isn’t asking wether you can ready to disengage. That question has been fully answered in a forum linked in a comment below. What this question is asking is, if you ready disengage, then when it does get to your turn are you already disengaged, and so can move away without provoking opportunity attacks? Below is the question as originally stated:
Can you ready the disengage action (say when the enemy gets within 5 feet of you), so that on your turn you can move away from that enemy without provoking opportunity attacks as you have already disengaged?
In other posts I have seen that readying disengage is legal, but I’ve not seen this particular question asked before.