It was sent before I finish/have finished writing?

[Tedwonny]

I was wondering what tense of the verb 'finish' I should use in the sentence:

The email was sent before I (finish/have finished/finished) writing?

[CONTEXT: Now, I've finished it. I accidentally hit the send button before I finished writing and I want to tell the reader that.]

Thanks a lot

 

[MikeNewYork]

I would use "finished".

 

[Tdol]

Or had finished.