我今年17岁用英语怎么说

I'm 17 years old .(一般不用把今年翻译出来的,因为am是进行式就说明是现在的年龄)

I am senventeen years old.
如果你是男的还可以说 I am a seventeen-year-old boy.
如果你是女的可以这样说 I am a seventeen-year-old girl.

i'm seventeen years old 或者最简单直接说 i'm 17

I'm in 17.
I'm at the age of 17.
I'm 17 this year.
I'm a 17-year-old boy/girl.
很多啊~~~~~~~~

I'm 17 now.