Natasha Henstridge was 19 in Species when she played the character 'Sil'.
That was over 29 years ago in 1995.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 49, and has starred in 53 movies in total, 50 of those since Species was released.
In Species, I think Natasha Henstridge looks: