Based on Ngolo Kante's profile, he was born on March 29th, 1991 so he is 31 years old. I don't think Chelsea will let him go because of his age because he has been a great player who has done so well for Chelsea so letting him leave when his contract expires won't be a good decision to take if you ask me but I doubt if Chelsea will offer him a three years contract because looking at his performance last season, Kante was not regular on the starting lineup for the blues due to serious of injuries so no team will take the risk of offering him such contract on his present age and injury condictions.
Yes, you are right. Probably Chelsea's board of directors is waiting for his contract to expire or wants him to make his decision so they know what he wants. Kante knows that Chelsea will not let him leave maybe that's why they are keeping his next move away from the media and other rumor spreaders. PS, I think Ngolo Kante knows his worth and he believes that he has done so well for Chelsea so he won't beg the team even though age is no longer on his side he will be a major target to other clubs if Chelsea refused to renew his contract. We will hear plenty of rumors about Kante before the end of the season if Chelsea didn't agree to his terms.