time of trade-in

Just to make sure and not have any future issues, I would suggest you reach out to Apple Support, they should be able to assist.

Get Support – Apple

https://getsupport.apple.com/

Call Customer Support (800) MY–APPLE (800–692–7753)

or online https://getsupport.apple.com/

or call AppleCare Support at 1-800-APLCARE (800-275-2273)

Outside the USA—Contact Apple for support and service by phone

See a list of Apple phone numbers around the world.

https://support.apple.com/en-us/HT201232

ocsa214 wrote:

Can I still send my old Mac in a trade-in process I've initiated when I bought the new one, even if I do it after the 14 days?

Thanks!

Yes. Not a problem.

You do not get the trade in value applied to your new purchase however, instead— a gift card for the amount after the initial 14 days.

Apple Trade In