Define Age Is Just A Number Meaning

A phrase used by people who oppose age restrictions, for example

a) Pensioners who want to continue working

b) People who sexually interested in minors

c) teens who seek to lower the voting age

Luigi: Mario, what the FUCK are you doing, you can’t have sex with her!
Mario: Oh yeah, why not?
Luigi: BECAUSE SHE’S FOURTEEN!!!
Mario: Yeah, What’s it to ya, age is only number, Luigi!
Luigi: Oh you know what else is a number?
Mario: What?
Luigi: NINE ONE FUCKING ONE, BITCH!!!