To find this a bit odd?

[Sienna333]

To be referred to as a "Tiny little thing"

I am mid 30's! The colleague who said it is 53. I find it quite condescending

Presumably it was about your stature, not your age? Not sure why ages are relevant. I've been called the same, can't say it bothered me, I am quite slim and fairly short. (And have been called a lot worse! )

almost certainly a height and/or weight thing.

Patronising.

I'm sure many of us have been called worse, that doesn't make this an acceptable thing to say.

Haha, Yes, definitely been called worse!
It was about height but was condescending and a bit over familiar I think.

You know how tall you are. You probably stopped growing 20 years ago.