Adjectives: position after as, how, so, too
After as, how, so, too and this/that meaning so, adjectives go before a/an. This structure is common in a formal style.
Grammar
as/how/so/too/this/that + adjective + a/an + noun
- I have as good a voice as you.
- How good a pianist is he?
- She is too polite a person to refuse.
- I couldn't afford that big a car.
- It was so warm a day that I could hardly work.
The structure is not possible without a/an.
- I like your country -- it's so beautiful. (not
I like your so beautiful country.) - Those girls are too kind to refuse. (not
They are too kind girls to refuse.)
note
For the structure with adjective + as in expressions like tired as I was ..., (see here).