First time purchase inquiry

[Myfirstwatch13]

I'm looking into purchasing a pre-owned 36mm women's oyster perpetual datejust 18k jubilee bracelet with the white face and diamonds on the hours. Want to know if it is imperative to have papers and how I can tell how old this watch is. It has the clasp with the crown but not engraved in the inner part of the bezel with serial numbers. Any information would be helpful.