He would be 44 on the day of the Trials.
A few quotes from the Runner's World article below:
“I still believe I can run 2:12 or 2:13, and maybe even faster on a great day. The question that I have to ask myself is whether or not I want to do the work to get in 2:14 shape. I really don’t know.”
“I am completely satisfied with what I have done in my career, whether I run another race or not. But on the same token, it is interesting to think about because it’s only 17 months away. If I am the people’s champion, maybe I should find out if the people want me to run or not.
“Maybe I should put it on Twitter and ask ‘what would you do if you were in my shoes?’ Maybe people would tell me to run. Or maybe they won’t.”
Personally I'd love to see Meb run again. And I think he would actually have a shot to make the team. Rupp has one spot on lockdown, but after that it's up for grabs.
https://www.runnersworld.com/news/a23610977/meb-keflezighi-nyc-marathon-olympic-team/