ずいぶんと古いな。の英語

It's very old.

It's too old.

very old

old and not suited to present needs or conditions; not modern; old-fashioned

It is a stale joke.

He is an old friend of mine.

so extremely old as seeming to belong to an earlier period

A slightly old painting.

That idea is old.

of a condition, being out of date

extreme oldness

I'm an old person?

old

It is a stale joke.

grow old or older

I am seen as old.

the degree to which something seems peculiar because it is antiquated

of something, the state of being old

of something, to become worn out after much use

the condition of being old-fashioned

of a thing, to become desolate

an old adage

Am I an old person?

My idea is old, right?

the act of attaching a high value to classic items

I will get older.

I will age.

a state of being stale

It is an old family―ancient family.

I'll discard my old jacket.