i have a question if the guy said he's 6inches long and 2.25inches girth...is that big or small?

It's likely evident he doesn't know what girth means. Girth=circumference at the base.

Length is average but girth is waaaaay to small to be measured right.

Girth sounds wrong-- that would be very tiny girth. Length is normal-- upper end of normal adult size. Most adult girth is 4.25 to 5.25 inches.

he's westerner...so is that mean skinny p...s?

About average for a Westerner, large for an Asian.

would all depend on how old the guy is

6 inches is a good length, but 2.25 is a skinny **** (but it'd be pretty easy to suck him). I'd guess that 2.25 is actually his estimated diameter, not circumference. If he's 2.5 diameter, he's over 6 inch circumference which is pretty thick. A **** with a 6 inch girth is made for fuc king, but he'll have to go slow getting in.