Beginner Triguy, looking at my first road bike from FB market place. is $700 for a Trek Madone 4.5 good?

Hey all i'm looking to get an upgrade from my mid 2000s mountain bike for triathlons. i've done one sprint tri on the 2007 fire mountain kona and it was a challenge Ha.

i found this on facebook market place and know very little about road bikes.
as a reference i'm 5'9" ~ 175lbs
$700 – Trek Madone 4.5 Full Carbon Fiber Road bike – They claim excellent condition

Trek Madone 4.5 Full Carbon Fiber Road bike /Excellent condition/Super lightweight .

– Frame size: 56 cm
-Super Lightweight .
– Aluminum Bontrager wheel-set .
-Race lite tires, size 700 c .
Shimano 105 components : 20 speeds .
-Shift smooth .
-Rim brakes .
-Original Trek parts .
– Bike computer .
– light