I'm just an outsider!用an 还是a?

I'm just an outsider!用an 还是a?
I'm just an outsider!
用an 还是a?

I'm just an outsider!用an 还是a?
I am an outsider
对
n.
1.外人;门外汉;局外人
To an outsider this looks like an idyllic life.
在局外人看来这好像是一种田园式的生活.
2.(比赛中)不大可能获胜的选手(或赛马)

当然是an了，outsider是元音开头的名词

用an,outsider是元音开头的名词.