Quick riddle because I haven't for a while... Hopefully it makes sense even with all the sounds-likes

Question

I was once this until I was no,

I did this just an hour ago,

You'll hear it if you're asked to wait,

or if you're told that you are late.

What is it?

Answer 1

It sounds like it could be

a homophone of ate including eight

I was once this until I was no,

Thought here is no in German (language tag) is nein so this sounds like

You were eight before you were nine

I did this just an hour ago,

You ate an hour before

You'll hear it if you're asked to wait, or if you're told that you are late

Both wait and late sound like (you'll hear) ate

Answer 2

I think you might be

A bell chime

I was once this until I was no,

One I'm slightly struggling on: It chimes $x$ times before stopping

I did this just an hour ago,

The clock chimes every hour

You'll hear it if you're asked to wait,

If you wait for at least an hour you will hear it

or if you're told that you are late.

Again slightly struggling: If you are asked to a meeting that starts at say 9, and you arrive slightly late the clock will already be ringing

Answer 3

I think it is related to being:

Punctual

I was once this until I was no,

I did this just an hour ago,

You were punctual as you arrived on time an hour ago.

You'll hear it if you're asked to wait,

or if you're told that you are late.

If you're early, you're informed you're punctual. If you're late, you're informed that you're not punctual.