When I started, I had a tight budget and zero patience. I bought an old CAAD 4 and after about 500 miles I had to replace the rear wheel. A thousand miles later the groupset was shot. My advice, save up a little bit more money and buy a new bike. CAAD 13, Giant Contend, Entry level Trek Domane, there are plenty of others.
That way you know what your getting and won’t have to worry about spending money on parts prematurely.
I bought a Cervelo C2 back in April at Competive Cyclist. I paid around 1700.