14 year old aircraft

Would a 14 year old plane really have a big difference to the amount of PAX that use my flights the Airplane Is a 737 700bgw

I also have a question about aircraft age. With a 14 year old airplane, what’s the rating you get for “aircraft age”. Does anyone know how the rating is given. For example: New = 5 bars; 3 years = 4 bars, 6 years = 3 bars etc.

Not not really just make sure your other ratings are good.