That girl is big enough to cook. = good

That girl is old enough to cook. = good

Is that coat big enough for you? = Does that coat fit you or is it too small?

That dog is big enough to put a saddle on and ride to town.

My car is big enough for me and five passengers.

Is you salary big enough to permit the purchase of that diamond?

I am big enough to take care of myself.  (Children love to tell parents this!)