upgrading MacBook Pro

You can check to see what you would get for the trade in. You may get a gift card which you can then use.

https://www.apple.com/shop/trade-in?afid=p238%7CsUcm0WBpo-dt_mtid_1870765e38482_pcrid_345423550316_pgrid_18213582367_&cid=aos-us-kwgo-brand--slid---apple+trade+in-e-product-

Well it depends on the condition of your 2014 Mac. You might want to bring it into an Apple Store to be looked at by a Genius technician.