I would go for the new bike if I were you. You won't be sorry. The new ride will be exceptional with at least 25mm tires and disc brakes too.
I am 66 and upgraded to a new carbon Trek Madone Series 6 back in 2014. I was mostly riding my Merlin Extralite when I went to the carbon. It was quite a change. The carbon is smooth over bumps even though it's a stiffer frame. Being lighter it also accelerates with ease.
I just upgraded the wheelset to Zipp 303's and can't wait to ride it...I am in northwest Indiana and it's snowing as I write this, so I won't be outdoors anytime soon.
Good luck with your new purchase, if you elect to do so.
Ride On!
Last edited by biketom5; 02-08-21 at 04:10 PM.