Poco doesn't change to poca???

My Spanish friend tells me this sentence is correct: Estoy *un* poc*o* loc*a* hoy. (I am female). Why isn't it: Estoy una poca loca hoy???? I don't get it. Sometimes poco changes to poca and sometimes it doesn't?? Hope someone can help me figure this one out! Gracias!

Hola Schrades, This is a hard one, one of those things ou just know because I've been doing it all my life... I had to look it up as I could only think of a few instances where you could use "poca".. anyway here is what I found.... The only time that "poco" seems to change into "poca" is when it's being used as an adjective describing a lack of quantity or quality... Some examples: Tenemos poca agua. La carne es de muy poca calidad. If anyone elser knows anythign about this please don't be afraid of correcting me. All the best and I hope that helped. Mauricio.

I appreciate your response. Despite my meager knowledge of Spanish, I have been given the task of teaching young children Spanish and I know they will ask me what I asked you as we spend a great deal of time matching adjectives to the gender of the noun they describe. I guess it is just one of those things! Gracias!